>JS engines in browsers should evolve to more general VMs, for which you can implement/port other languages.
You do understand that when this happens (and is spread enough to use in production), the web framework and tooling fatigue will be 2-3 times worse.
It's not just that everybody and their dog will write their own framework (as now), they'll split even more and do it for 10 languages... And expect the same dilution of effort for libs too...
I'd actually prefer a better JS replacement, that is, a new, single, language that draws from it and gets rid of all the caveats fixed (lack of ints, coercion rules, small std lib, optional types, even better designed for high speed JITing etc), than seeing Python, Clojure, Ruby, Lua, PHP and 200 others re-implemented in web assembly...