I feel that this article ignores the biggest advantage of LaTeX: templates and macros. Word processors or WYSIWYG editors make it very hard to share typesetting style. On the other hand, if I want to format my text into an ACM paper there's a template for that, if I want to make a PDF for my 'zine that I'm publishing, there's a different template for that, just like there's a template for publishing my resume. Iterating on this style can happen independently to iterating on the content, and you can let other LaTeX users tweak on the actual typesetting.
I do agree that reading LaTeX or TeX in general is a bit hard, but there's been a lot of ergonomic improvements in that regard, which the article only mentions in passing. ConTeXt  is a pretty nice system with a much more "sane" set of default directives. There's also LuaTeX  if you just want to write Lua. Scribble  can also generate both great web documentation and good PDF documentation. On that note, I really don't find TeX that difficult to write but that is probably just pure personal opinion.
Nothing about claiming that we live in Douglas Engelbart's future has anything to do with creating technologies or systems that are "superficially similar" to previous, successful systems. I think this article is conflating iterative innovation (with all of its pluses and minuses) with the claims of technologists.
My main complaint in this essay is that such a claim is a misrepresentation of history: we don't use tech that is deeply influenced by these seminal projects, but instead use tech based on extremely different goals & constraints.
This is a common problem with popular history-of-science (and especially popular history-of-tech) & comes in both a strong and weak form.
The strong form is "we live in the future that <figure> imagined/wanted" -- something that's almost never true. Engelbart was not as outspoken in his criticism of the direction of development as Nelson & Kay, but he wasn't quiet about it either. Strictly speaking, these seminal projects had specific goals that they achieved far better than the later work inspired by them did.
The weak form is along the lines of "<project> influenced later work", which is weak enough to be almost meaningless. The most important elements of these projects are typically lost in the churn, meaning that while the influence is obvious it is also shallow.
Ultimately, this is a complaint about the historiography, not the development techniques. (I have problems with both, but the latter is covered in other essays.)
When we tell ourselves a neat story about the lineage of some piece of modern tech -- say, that the modern desktop comes from nLS or the Alto -- we erase the elements that differ, either forgetting them entirely or suggesting that they were mistakes. By telling this story, we lend to modern interfaces some of the idealism that animated the earlier projects.
However, the elements that are missing from modern systems are often precisely those most required for squaring the system with the ideals -- Smalltalk's live-editing and composition, for instance, or Xanadu's permanent addressing. So, to tell the history honestly, we should not allow ourselves to misattribute the ideals of nLS, Smalltalk80, & Xanadu to the Macintosh or the Web respectively.
Allowing ourselves to become confused by this kind of narrative supports some dubious marketing, which makes it more dangerous.
For instance, the Macintosh cribbed a lot of philosophical ideas from ARC (augmentation / man-machine symbiosis vs 'bicycle for the mind') & popularized them, to the point that these ideas are more readily associated with Macintosh marketing than with ARC, and yet the Macintosh was a substantially worse fit for this than its competitors in the market at launch! It weakens the original idea (by implying that the Mac was on the right track, or that the Mac was the best people could do in the early 80s, when really the Mac wasn't seriously trying to do any of these things).
Re: iterative innovation --
Iterative innovation doesn't really come into it. These projects were the result of rapid iteration in the first place. Our modern tech is not based on iteration on the seminal projects, but on taking a handful of ideas from those projects and implementing them in a different context. (Squeak is derived from actual Alto & Smalltalk80 tech, but the Macintosh is not. There's an actual Xanadu lineage, and the World Wide Web isn't part of it because TBL wasn't privy to the state of the art in Xanadu tech as of the late 80s.) Often, the ideas aren't fully understood, or they aren't adapted to the new context, or it's not considered whether or not necessary adaptations make the idea itself pointless -- we're talking about outsiders implementing new projects largely based on marketing materials. There's nothing wrong with doing that -- in fact, it's a great way to come up with potentially-interesting ideas of your own -- but it's not an effective way to add meaningfully to a lineage, particularly when you're trying to do it with a fraction of the original resources.
 The Lisa & Macintosh projects had a lot of ex-PARC folks involved, and so presumably many of the developers were fully aware of the differences. But, the driving design force was Jobs, whose understanding of PARC's design philosophy was very shallow, and they were working with technology substantially less beefy than the Alto, particularly in the Macintosh (which was specifically designed to be cheaper than the Lisa, leading to a lot of cut corners). In other words, in this case it's not completely accurate to say that it's a group of outsiders, but the decision-maker had an incomplete understanding of the original project the constraints on time & hardware had a greater influence on design decisions than any inherited idealism. Cost-cutting measures inherited from that project continued to be copied in other projects it influenced long after they ceased to be necessary.
> My main complaint in this essay is that such a claim is a misrepresentation of history: we don't use tech that is deeply influenced by these seminal projects, but instead use tech based on extremely different goals & constraints.
I don't see a proof of the assertion that the tech is extremely different or even directly derived from these concepts. Kay has written at length about concepts that he wanted to see that were never realized (missing systems with no Smalltalk80 style objects, bemoaning the iPad's utility as a consumption device but its failure as a production device), but you seem to be making a claim that there are strong, foundational ideas from these seminal projects that were not only ignored, but apparently deliberately ignored for some nefarious purpose.
> The strong form is "we live in the future that <figure> imagined/wanted" -- something that's almost never true. Engelbart was not as outspoken in his criticism of the direction of development as Nelson & Kay, but he wasn't quiet about it either. Strictly speaking, these seminal projects had specific goals that they achieved far better than the later work inspired by them did.
I'm less familiar with Nelson's writings, but Engelbart didn't have much to say about how his writing has been construed, and while Kay has publicly voiced his disproval of current technologies, at no point has Kay attributed malice or otherwise nefarious ends to the reasons for which his ideas went unrealized.
> The weak form is along the lines of "<project> influenced later work", which is weak enough to be almost meaningless. The most important elements of these projects are typically lost in the churn, meaning that while the influence is obvious it is also shallow.
I'm unclear as to why a weak influence disqualifies something from being an influence. You note that "There's nothing wrong with doing that -- in fact, it's a great way to come up with potentially-interesting ideas of your own -- but it's not an effective way to add meaningfully to a lineage" but I do not think that neither you nor I have the ability to define what this lineage is. Like most history, the continuum of lineage is simply a convenient analytic tool for understanding large swaths of events. It's like trying to pin a date for the exact fall of the Roman Empire, an exercise in sophistry.
From the article:
> These folks weren’t trying to predict our current future. They were trying to create a future worth living in, & we failed to make that happen.
Again you seem to be attributing to these seminal works a set of qualities that were apparently central but unrealized when I don't think anyone but the author of the works themselves has any right to do this.
It's unclear to me whether the ideas of Nelson, Kay, et al. were failed to be realized because of some nefarious reason, because of ambivalence, because there simply wasn't a demand for their ideas, or because of a complex interplay of economic and social issues that thwarted adoption. I believe you've taken selected portions of their ideas and placed them on a pedestal, and centered their works around these ideas as you interpret them rather than other aspects. There's many good ideas and observations from these visionaries that continue to go unrealized, but as with any technology that lost, we should be careful when looking at the technologies to see why rather than coming up with simplistic explanations involving greed or malice.
> at no point has Kay attributed malice or otherwise nefarious ends to the reasons for which his ideas went unrealized.
Neither do I. It's unfortunate that relatively few people have continued Kay's work, but it's largely because they don't understand it, not because they're deliberately misrepresenting it. Likewise with Nelson & Engelbart.
(With regard to Engelbart, he wrote less in public about misrepresentation of his work, & I mostly know how he felt about it via Nelson. I don't think Ted's lying to me, & the two of them were close.)
> I'm unclear as to why a weak influence disqualifies something from being an influence.
A weak influence does not disqualify something from being an influence. However, a weak influence isn't meaningful -- I am weakly influenced by TV shows I've never watched, for instance.
> It's unclear to me whether the ideas of Nelson, Kay, et al. were failed to be realized because of some nefarious reason, because of ambivalence, because there simply wasn't a demand for their ideas, or because of a complex interplay of economic and social issues that thwarted adoption.
Nelson, Kay, & Engelbart actually did realize their ideals -- at least, at a small scale in prototype projects. We know what their ideals were because they wrote about them, & we know that they were realized because we've seen those projects.
Later projects that claim to be inspired by them do not have these qualities, because they do not have the same goals. (I'm not, in this essay, judging them for not having the same goals. I do that in other essays. I'm judging bad journalists for claiming a stronger link than is justified.)
Again, I'm not complaining about the history. I'm complaining about the historiography.
Highlighting a lineage between these projects & modern systems is misleading, particularly when people make the strong form of the argument (that modern systems represent what these projects envisioned). Such a misapprehension is valuable for marketing purposes, since it allows modern systems to borrow clout: we ought to be very careful about feeding that kind of mythology, since it's both dubious and backed by powerful figures.
It's accurate to say that the mouse came from nLS, that overlapping windows, icons, and drop-down menus came from PARC & the Alto project, and that jump links came from Xanadu. But, it's inaccurate to characterize nLS primarily as the origin of the mouse (seeing as how it had defined itself as a groupware system for creating human-machine symbiosis), or to characterize the Alto primarily as the inspiration for the Macintosh (since Mesa also inspired plan9 & Oberon and since Smalltalk80 was such a rich & interesting system in of itself), or to characterize Xanadu primarily as the inspiration for the web (since jump links were one of many features, all balanced together carefully in a nuanced overarching design, which the web did not duplicate because TBL did not understand it).
When we remember seminal system primarily for the elements shared with economically-successful modern systems inspired by them, we create a narrative that discounts the value of the parts not adapted -- a clean linear narrative where the winners were fated. But the winners got lucky, & we have a lot to learn from the losers & from the seminal systems that inspired the whole lot (by dint of being allowed, due to lack of market pressures, to be more creative).