

Because of the CORS settings on Google’s servers would tell your browser to not go forward with the request. There are two ways it could eventually be possible:
Fair enough, that’s interesting. I assume this only applies to the non-web clients. On the web, it would not be possible. You can verify by looking at the outgoing network requests on this random video for example: https://invidious.privacyredirect.com/watch?v=qKMcKQCQxxI
Invidious and YouTube piped (and LibreTube) by default load the videos server-side, as opposed to GrayJay, NewPipe or Smarttube.
It has advantages (mostly that your IP address is not shared with YouTube, and it allows users from countries where YouTube is blocked to still access it) and inconvenients (much harder to keep up when YouTube actively seeks to block them).
Unfortunately, I think that while ad blockers won’t work as well, they will still work good enough that most won’t bother making the switch.
https://blog.getadblock.com/how-adblock-is-getting-ready-for-manifest-v3-6cf21a7884f6
https://github.com/uBlockOrigin/uBOL-home/wiki/
https://adguard.com/en/blog/adguard-mv3.html
https://www.reddit.com/r/uBlockOrigin/comments/1067als/comment/j3h00xj/
The main issue I see is the slow update of filters (which require an extension update). This might make YouTube win the cat and mouse game. Where YouTube updates(ed?) their blocking detection multiple time a day.
I know they do, but it’s lacking so many languages.