But then they'd be one antitrust investigation away from losing it all.

Why waste effort on something that's a rounding error at best?

It is because of such effort that they are rounding errors: https://arstechnica.com/tech-policy/2025/04/google-loses-ad-...

What do you think uBlock Lite is for? They'll continue to cripple it until it is unable to block YouTube ads while still being able to block everything else.

If they'd ever allow such a thing to exist.