Sure, but ESBuild is here, it works, and the subjective speed improvement is just fucking massive.
I’m sure you could get something with similar performance in JS. I’ve messed around with JS daemons, so you don’t care about startup time for programs like tsc and whatnot. The problem is that it’s just a pain in the ass to get any of this to work, whereas ESBuild is just fast.
Maybe these problems with JS will get solved at some point, because we haven’t exhausted all of the possibilities for making JS faster (like the author says). However, when you write the tools in Rust or Go or whatever, you get a fast tool without trying very hard.