TheOnlyMego

This means that when developing your application you need to keep track of what differences each browser has, and write/use polyfills or conditionals to ensure that your methods work as expected on all platforms.

core-js has existed for nearly a decade

"You didn't hear that"

that puts a barrier on new users and enforces echo chambers

Only if trust starts at 0. A system where trust started high enough to not filter out posts and comments would avoid that issue.