Also notable that the way changes are introduced to the different languages is so different that this is just hard to really look at. Notably, elisp of today is not dramatically different from elisp of 20 years ago. JavaScript? Basically a brand new language after ES6+.
ES6 was released 16 years ago. I'm building on top of ES6 like it's rock solid, and so far I haven't been disappointed. After ES6 the langdev process changed materially, and it now rewards introducing language features that are, in my view, half-baked. I have had to take over parts of the work of the standards committee to be able to do this project at all.
Oh for sure. I'm not trying to make a case against Emacs or Elisp or anything. Mature tech is highly, highly valuable. I just wanted to know if JS could do it. Could it, can it host a whole unix-y, emacs-y OS?