Also, given that DSSSL was an early contender against CSS (and a great deal more powerful), we could have basically had Scheme there too. https://blog.cloudflare.com/the-languages-which-almost-becam...
Lastly, because S-expressions can represent everything that is representable in SGML/XML/(X)HTML, but more succinctly, we could have basically had Scheme instead of HTML.
Imagine if, instead of JS/HTML/CSS, we had... Scheme. I'm pretty sure that the alter universes where this happened also all have peace, warp drives, and working cold fusion.