Wouldn't this require Chrome to download models on the fly or pre-package multiple models?

That doesn't really seem possible (mobile data connection) or convenient (Chrome binary size, disk space) for the user.

Only that it will take 5-10y to be regulated, until they will have to pay a measly fine, and let users choose. But then we will have the same game as with GDPR conformity now, companies left and right acting as if they just misunderstood the "new" rules and are still learning how this big mystery is to be understood, until a judge tells them to cut the crap. Then we will have the big masses, that will not care and feed all kinds of data into this AI thing, even without asking people it concerns for consent. Oh and then of course Google will claim, that it is all the bad users doing that, and that it is so difficult to monitor and prevent.