What I usually never see mentioned is the fair use doctrine. As soon as some website (reddit/yelp etc) is able to prove that their data has been used to train an AI that is monetisable, they'll be up in arms.

I believe this tech is so different and revolutionary, that the lawyers have yet to wrap their head around it. I predict a million lawsuits incoming any time now. This I believe is the primary reason for Google not releasing any product before the water gets tested. For what its worth Google already has access to lots and lots of data that it owns, that it can train its AI on (Photos, Gmail, Docs, obviously Search and probably YouTube as well)