alt Hacker NewsI shouldn't have defended the API or age rating solution. It's just a trap in hindsight. That kind of solution must be rejected altogether even if it's the OS checking the app/website's age rating header, because we'd be giving the OS oligopoly (Apple, Google, Microsoft) way too much leverage, and in the long term they're going to make it so that you can only run their approved apps because unapproved apps didn't implement their age rating API. And there is no competing OS to fix that situation if those same companies keep the bootloader on their hardware locked. That still puts authority over children in the hands of governments and corporations rather than parents.
I stand by my original comment. No new laws are needed. All of the features outlined in 1), 2), and 3) should be user-controlled, and there's no need to send info over the air.
You can still get hardware that you can install your own OS on. But you have to be deliberate about picking it out before a purchase, rather than hoping to unlock a random carrier phone down the line. For example my phone is a Pixel running Graphene. It has a locked down bootloader that could only be unlocked with the online consent of Google. While this most certainly chafes me (and if I could snap my fingers and make such schemes blink out of existence I would), I do have to admit that it really isn't that debilitating.
The unlocking process zaps the userdata partition. This security model would totally suffice for locking down a child's phone. If the child zaps their phone and erases everything on it, then the parent can handle that out of band.
For the general problem, I would say that there has been a longstanding market failure here, in that parental control software isn't widespread or straightforwardly usable across different websites. Your 3 points don't really address that. (2) has been doable on standard desktops forever, and (3) just pushes mobile devices back towards the capability of desktops (which on its own is laudable!). But standard desktops have had these capabilities for decades and still haven't evolved the kind of straightforward parental controls that most parents are demanding.