We should assign one or two adults to children who provide for them, and prevent various dangers, including online ones, from reaching them. It sounds like a lot of effort, but it is also the most important task on the planet.

A generation of kids have grown up with just such assigned adults, who overwhelmingly did not apply sufficient oversight to the kids' use of social media.

In large part that's because, if they'd done so, the kids would've been socially isolated from their peers, at least the most normal ones with the most normal parents, which are the kinds of friends most other normal parents want their kids to have.

It's a collective action problem, except instead of "I can be better off if I ignore what I know is best for society", it's "if I ignore what I know is best for my kids psychologically, they will still have friends, and social media brainrot is a lesser evil than socially isolating my kid from all the normal kids at school."

And also, giving kids social media interaction devices is a convenient form of babysitting. It reduces up-front effort of parenting.