It's not the problem of JS, it's what is being done with it. It's about bullshit and bloat, about lazy-ass developers, designers showing off and the web being fashion-driven industry. It's about ads and tracking.

The only way to fix it JS-level is to bake a requirement into the standard that the code size limit for JS is 256kb. If a company can't fit their "value-added features" in it, that's their problem.