Properties of a language shape the tooling and culture that develops around it.

JS has exploded in popularity when Internet Explorer was still around, before ES6 cleanup of the language. JS had lots of gotchas where seemingly obvious code wasn't working correctly, and devs weren't keeping up with all the dumb hacks needed for even basic things. Working around IE6's problems used to be a whole profession (quirksmode.org).

Browsers didn't have support for JS modules yet, and HTTP/1.1 couldn't handle many small files, so devs needed a way to "bundle" their JS anyway. Node.js happened to have a solution, while also enabled reusing code between client and server, and the micro libraries saved developers from having to deal with JS engine differences and memorize all the quirks.