> I'd prefer JavaScript kept evolving (think "strict", but "stricter", "stricter still", ...) to a simpler and easier to compile/JIT language.
This is / was ASM.js, a limited subset of JS without all the dynamic behaviour which allowed the interpreter to skip a lot of checks and assumptions. This was deprecated in favor of WASM - basically communicating that if you need the strictness or performance, use a different language.
As for JS strictness, eslint / biome with all the rules engaged will also make it strict.
ASM.js and 'use strict' have completely different purposes. One is a performance thing and is (or was supposed to be) used as a compiler target. The other is all about making the programmer’s life easier by disabling features that conflict with principles of maintainability.