I’d be shocked if the best and the brightest that Alphabet can buy can’t figure out a reputation system, manually-reviewed with AI assistance, or some other way to approve content in a convenient manner.

Don’t forget also that Alphabet is swimming in money. They can certainly afford the manpower to make it relatively seamless for the user. And I really doubt users can’t be trained to associate a few hours’ wait of a completely new, reputationless user, or a user who is using an unknown device or VPN, with a better quality of site experience because the videos are screened.