Webassembly started its life as a JS hack, called asm.js: https://en.wikipedia.org/wiki/Asm.js, which itself was fully capable of running Quake.

Here's the Unreal engine demo from 10 years ago: https://www.youtube.com/watch?v=XsyogXtyU9o

now you can make web apps in your compiled language of choice (limited choice) and not worry (as much) that its not fast enough