>It is absolutely an inferior and chatty protocol for any other application though, like try to watch a youtube video in chrome through it.

This is extremely misleading. Web browsers (and games) are the worst case for X11's network transparency. The overwhelming majority of applications belong in the same category as xeyes.

> the original X network transparency's modern analogue might very well be the web

It's Arcan, which solved this problem without sacrificing network transparency at the altar.