Let's suppose the cause really is as simple as "parents can't be bothered to parent". By default, this will continue to be the case. And realistically we're not going to fix it by telling bad parents to please start being good parents. So what do you actually want to do? I'm not saying it's this or nothing, but if you don't have an alternative policy that might actually help, I don't take much comfort in the idea that the kids who are damaged will have _parents_ who totally deserved it.
There are some alternative policies, for example, banning smartphones in schools. This doesn't completely solve the problem, of course, but at least it limits social media use while the children are under direct supervision of the government.
A more extreme policy would be to treat smartphones themselves the same way we treat alcohol and cigarettes, enforcing an age minimum at the point of purchase. Of course the giant tech corporations would fly into rage over this suggestion and lobby heavily against it.
