Someone on HN suggested parents set devices up for their kids and Browsers and OS's gate by age. I haven't really been able to fault this idea.

State mandates verification and stuff like this makes me suspicious that this is much more than "protecting the children". More advocacy of alternative solutions please.

That's the California approach. Devices whose primary user is a child will have to provide a way for parents to provide an age range for the child, and an API that apps and app stores can use to check that so they can avoid doing things that are supposed to be age restricted.

It has been discussed a few times here, and those threads are always full of people proclaiming that it will be the end of free and anonymous internet for all of us and allow tracking everything we do by both the government and any site we visit.

Indeed, I truly don't understand how simply enabling parental controls onto mobile devices handed to kids which then gets advertised to each website/app that they use isn't sufficient.

You make it an opt-in feature to "self-broadcast" that this device is being used by a minor. Solves 99% of the use cases. And for the remaining 1% — the really determined teenager — they'd never be stopped by this anyway. They'd social enginneer their way to access somehow.