Don't underestimate prototyping nature of js that allowed for exporing design space at higher speed throughout the years.

Reminds me when I was working on distributed filesystem at LiveDrive more than 10 years ago, wrote working prototype and few iterations in Ruby before rewriting it in C - somebody said "(you did it) because Ruby was slow/crap?", I said "no, because Ruby was essential (to do it quick)".

Also interop with those tools (though wasm) is relatively new.

Js/ts ecosystem is actually quite nice now with this option to use wasm for performance - while still keeping "works on the server and in the browser" intact.