but what if it is a surface layer built out of those languages and frameworks? Even if it's not optimized and technologically eloquent, it's already being rammed through now with libraries like Google's A-Frame.

Myopic maybe, but only from a select perspective. Those languages have been the most democratizing in CS history. They're the ones a lot of people seem to be the least intimidated by, at least at the outset.

I'm sure it will come back down to lower-level work because the higher level processes will soon require it. That said, I don't personally foresee some new, young group yet writing a viable alternative to Windows, macOS, Linux or any variants thereof. There's little point, and the battle would be a hard one to win. It's much easier to tame new ground in order to make one's place. That aspect shouldn't be underestimated in its influence.