The thing is that TeX math requires a lot of shit, it basically means implementing a full Tex parser and parsing a bunch of things that exist in libraries in the web browser as well as rendering support. MathML being an xml derivative only requires rendering support.
Full TeX is not a good fit for the web as it's designed to typeset paginated documents at a size known at write time. You would standardise on some subset of Math mode LaTeX like MathJax does.
The challenge is then picking the subset of LaTeX.
Then maybe someday someone would write a web-LaTeX preprocessor with macros and the like.
It would also mean another Turing complete language embedded in browsers, in addition to… JavaScript, XSLT, GLSL (WebGL), WebAssembly, CSS itself if you squint, fonts, WebSQL (TIL some browsers still support it)… probably more I’m not thinking of.
> I do not encounter TeX users who write their own macros often.
But they use packages that they got off CTAN that were written by someone who is not at central office (not that there is a central office, but one would be needed if you stripped out the ability to write serious macros since there would have to be someone adding approved features).
Developers use macros. Now since they are developers, they had less problem develop with a programming language and may prefer to do so than using the TeX macro system. The alt-TeX can simply be extended with plugins or modules.
If you mean that SVG is Turing complete, I was thinking of it, but not having much experience with it, I'm not sure what exactly is Turing complete there (without XSLT, which I mentioned).
