Re: Nope. LaTex shipped after the Mac and long after the Alto..."notes"...you're joking?
I think you misunderstood my comment. I mentioned that WYSIWYG existed at PARC then (I visited PARC in 1974, and saw what I think was an early version of Bravo). I suspect that Knuth knew something about it, given the distance between Stanford's CS building and PARC, but he was trying to build a program that would typeset his books the way he thought they should look, and WYSIWYG just didn't cut it in those days. I suspect he also knew about the Bell Labs pic/eqn/troff toolchain, too. The guy does encyclopedic research.
As for writing a paper versus shipping copies of software, we were looking at when these various tools were designed, in other words, the intellectual roots, as shown in papers, etc. If that makes me an academic, guilty! I'm retired now, but taught software engineering not only in universities, but also to industry. But shipping things has nothing to do with what's possible: a lot of defunct word processors shipped lots of copies, but really were not very good. Re WriteNow: I'm glad it satisfied your needs. Many people find MS-Word or FrameMaker satisfies theirs. But I doubt that WriteNow, in 1986, could have produced a paper that, say, the American Mathematical Society or the Association for Computing Machinery would have accepted as camera-ready copy. That was Knuth's goal, even though it may not have been yours.
As for that document I produced with it, it was a user manual for a simple programming environment I wrote for first-year students. No math at all, but lots of structured text (e.g., command reference descriptions). I can confidently say that no other software accessible to me at the time could have done the job, as at that time TeX could drive a laser printer and nothing else I had could. Admittedly, I wasn't using TeX for the purposes Knuth intended, but it satisfied my needs.
I can also say that LaTeX at that time did not satisfy my needs, primarily because its font support was primitive. I co-authored a book in the early 1990s, and used a format I developed that looked LaTeX-like, but handled my font needs (I too was aware of Scribe). However, font handling has vastly improved in LaTeX, and I stopped using my custom format long ago.
As for 10x the work, I was forced to use FrameMaker for one project when I worked for $BIGCOMPANY. I found it adequate for the job, but it took me about the same amount of time as a comparable job done in LaTeX. Any of these systems (even MS-Word) has a significant learning curve. I used to give my students the task of creating a style sheet in Word for their documentation; they found this a real challenge. But once one has the tools, actually knocking out documents is quite easy.
I did not understand your comment about flakiness. Knuth is famous for logging every bug ever found in TeX; I found even the prereleases fairly solid, and once it went into release, it was very solid. LaTeX may have been buggy in those days, though I never used it until the late 90s. Even if it was, my reply is simple: Windows 3.0 shipped a lot of copies, and it had a few bugs.
I fully understand that you perceive no need for TeX, and agree that it has limited domains (e.g., you wouldn't do newspaper layouts with it).On the other hand, it has been used to typeset many books. Pandoc uses it as a backend when you convert HTML or Markdown into PDF. It has been used in industry for everything from railway timetables to producing telecom bills. There is a real difference between “I don't need this” and “this is useless”.