A lot of this basically reads to me like hidden tech debt: people aren't updating their compilation targets to ESx, people aren't updating their packages, package authors aren't updating their implementations, etc.
Ancient browser support is a thing, but ES5 has been supported everywhere for like 13 years now (as per https://caniuse.com/es5).
Ancient browser support is a thing, but ES5 has been supported everywhere for like 13 years now (as per https://caniuse.com/es5).