Why not Web components in 2022?

Hey Frontend devs, I was curious about the state of web components and why they haven't caught up? Are they widely supported already? As far as I see, Github already many web components if you view the page source, whole FireFox UI is all made of web components and of course Github won't put them if they weren't widely supported I assuem.

So if that's the case, Vanilla JS (or Typescript) with custom written components with some SPA routing (think page.js or similar) should go pretty far especially when things Playwright can pierce shadow DOM as well and no need for whole heavy toolchain and frameworks such as React. No?

Thoughts, caveats, experiences, ideas?