Despite the existence of WebAssembly, which some have suggested to be able to run a non-JS language, I just have a hard time seeing anything non-JS get popular for the web. The in browser debug/development environment just works too well.

Short of Google implementing something if Chrome hits 85-90% of all use in an attempt to dump JS it just doesn’t seem like something that would happen. I doubt any browser team would want to implement multiple languages. I doubt Google would want to switch.