It's especially true when you lower the bar to entry. There's lots of CRUD because anybody can make something. It also means there are lots of things.
If you want well-documented stuff, vote for it by not using things that are poorly documented. Or figure it out and write the documentation. That's how open source works (or doesn't work), and JS/Webdev is not unique in this regard.
Microcomputers were poorly documented way back in the 70s. I'll be there were people complaining how shoddy they were on that basis, but that low barrier to entry led directly to us having this discussion on Hacker News today.