prohibit all proprietary software

Parents can just do this. It's far more expensive to not do it.

>logs into his seven year old five digit karma hackernews account >tells people to stop talking online

I expect more kids will switch to playing more games on their phones with their friends. Whoever thinks the kids will instead put down their phones and starting go out more often has lost touch with reality.

This is the obvious solution, but implementing it would be a herculean effort. Not because it's technically difficult, of course.

Consider the incentives of all involved powerful groups.

You have social media giants who want to addict and advertise to users. The hate your solution, obviously. With the ID checks they lose out on their younger users, but they also get cover for even more aggressive behavior as nobody can credibly yell "think of the children!" at them.

Then you have government officials who are nervous about their lack of effective control over modern media. Your solution offers them nothing and loses them points with those powerful business leaders. It opens them up to attack from the right for being "too hard on business and stifling innovation." The ID checks, on the other hand, give them a mechanism and lever to crack down on any sentiment in the public that runs counter to their or their friends' interests. It even polls pretty well with an increasingly large number of paranoid and distrusting voters.

There's no contest at all between the routes before us. Only a huge political upheaval could divert the world from this path. The indicator to look for in a representative is a willingness to champion policy that hurts entrenched political and economic power while providing straightforward utility to average citizens.

Parents should instead regulate what their kids can do.