this is plainly inaccurate. most people only use very few packages, which exists only for legacy reasons, they should be really integrated. TeXmacs provide all things 90% of people need.
"here are WYSIWYG editors for TeX as well." not there are not. Apart from TeXmacs I know of no editor which give you on the screen the same result you get on the paper. LyX has not such a feature. If an approximation is ok, then fine, but I do not think you can call it WYSIWYG. Is something else. And it requires a lot of work to do it correctly. You should at least appreciate the technical merits, even if you prefer to use LaTeX for its ecosystem. But as a user of both I see the clear merits of TeXmacs in terms of quality of my work (mathematician), I can focus more on what I'm doing, instead on deciphering the mess of the LaTeX formulas and try to find where to put a correction. I can give online lectures with it, discuss on zoom while scribbling on a TeXmacs document, much of the work I was doing on paper I do now directly on the computer. To me there is a clear difference in the user experience between TeXmacs and LaTeX and I will never go back to write LaTeX if I can help it (I do it sometimes, if my coauthors are using it and do not want to try otherwise).
TeXmacs has its own macro language. The equivalent of \newcommand is \assign together with \macro (yes, TeXmacs has proper first class macros, like any respectable language, e.g. Lisp). And macros arguments can be edited visually, here's an example: https://twitter.com/gnu_texmacs/status/1251554336842407938
looking at some other comments in this thread and also to my experience, it not unnecessary clarification in the large. I'm glad you just were doing some humor. :)
The phrase "it uses LaTeX" means that it runs the program LaTeX or that it need the "LaTeX format". Neither is true. Similarly you would say that "PanDoc uses Word?" or that a program that export to Word use Word. To me if you want to say that a program exports to a particular format just say so. If you want to say that a program needs a working installation of another program Y to work then you can say "it uses Y". So I think it is not correct to say that TeXmacs uses LaTeX. It can import/export it, like it can export/import PDF, HTML and other formats. TeXmacs does not need a working LateX installation to work. It comes with all its batteries included and on the Mac the app weight < 150 MB. That's all you need (including the LaTeX importer/exporter which is written in Scheme).
I would really like to have names of packages you use regularly and you think you will miss in any other system. I can think only of TikZ, and again, for targeted purposes like DSL you can always ask TeXmacs to run LaTeX and get the output. See e.g. https://twitter.com/gnu_texmacs/status/1605167149173153793
You can just pick the AppImage if you like Linux. No installation needed. If you are on Mac, then you just need to give permission to run the software, it is not a specific problem of TeXmacs, it happens because TeXmacs executable are not signed. There are many reason you can turn down a software. any software. The point is: to whom are you making a favour? :) TeXmacs is free and make you save a lot of time. So I would say it is worth to spend a bit of it learning to use it properly. To be effective it require you to unlearn some LaTeX habits. But again, it is up to you. What I think is unfair is to deduce from these features that it is not a useful piece of software.
This is not our experience as TeXmacs users. 90% of the time you are always using the same features, which are well implemented in TeXmacs. Maybe you can show me some of your documents which require TeX, so that I can understand the uses cases you think about. If you look at documents on arXiv there is no reason not to use it. Of course TeXmacs will never take over but it allows us to focus on the content and not on writing TeX. Time gained for more productive tasks with no backside. I guess people praising LaTeX should give explicit examples of what they mean by "huge package ecosystem", in the sense of a measure of how many of those packages are really used by 80% of the scientific community. And btw, TeXmacs can just run TikZ fine, if you really need it. https://twitter.com/gnu_texmacs/status/1509200571537973255
I'm not sure what are you referring to. TeXmacs is used everyday by many people, at lest 3/4 of my students wrote their PhD thesis with it, some of them enterely, other the initial draft. All my papers are written with it, lecture notes, presentations, letters. My experience is the same of many other people. Even comparning TeXmacs with AucTeX+Emacs is misleading. Totally different user experience. TeXmacs does not have yet a fully stable collaborative functionality, but the functionality is there and it experimentally work. Maybe one day will be completed and you will not need to rely on a central server to use it, just fire up a TeXmacs instance to be the server and connect the others: https://mobile.twitter.com/gnu_texmacs/status/13910657725338... So, slowly, but we will be there too. :)
TeX is a typesetting language. Like Postscript. There is no particular reasons humans need to write it. That is the reason LaTeX was invented (and Context). We need formats, like PDF or HTML, to exchange and reliably use informations and describe documents. TeXmacs is a document preparation system from the UI to all the other things needed, in one place, in a uniform architecture. It has its own internal format and it exports to TeX/LaTeX as it can export to HTML or PDF. Publishers do not need TeX to store documents, indeed TeX is no a particularly good way to store data. It is what it is: a typesetting language, not a document description format. So I do not see any conflicts between using TeXmacs and then sending a TeX file to the editor. Anyway in most of the cases them (or nowadays most likely you) need to reformat it to the standards of the particular journal. I (and many others, including the main author of TeXmacs) work in academia and I have no problem using TeXmacs everyday to do my work and then send to the publisher a nice LaTeX file, which I do not have to edit by hand. I'm (mostly) TeX/LaTeX free since 2006 and very happy about this.