As to 1) The prisoners dillema is a pretty basic example of how the best possible co-ordinated action is not necesarily the best possible individual action. i.e.
other kids not on social media/ your kid not on social media Δ0 happiness
other kids not on social media/ your kid on social media Δ-3 happiness
other kids on social media/ your kid on social media Δ-10 happiness
other kids on social media/ your kid not not social media Δ-50 happiness
Maybe some form of co-ordination might be in the parents best interest... maybe some form of representative could do something about it if it's in the kids best interest?
To reply just as flippantly: We could take the same aproach to alcohol and gambling, drop all age restrictions and put all the responsibility on the parents, then businesses will truly be able to run efficiently.
Of course good parents have to be involved in raising there kids well but that doesn't mean we shouldn't subsidide education or restrict companies from sending kids down coal mines(even if they really want the money). Mostly because good parents can fail and bad parents exist and if society isn't going to aim for turning kids into good adults then it'll just get worse generation on generation.
The approach to alcohol isn't all that different: It's entirely legal for a parent serve alcohol to their kid. If it were possible for each store to determine the parent's wish's, we'd probably have that.
Parents control the phone and the phone plan. Parental controls that exist today can set how long an app can be open per day. What's the outcome from suing Meta that's more effective?
I agree that policy should protect kids and to do that it needs to be effective, not just cathartic.
other kids not on social media/ your kid not on social media Δ0 happiness
other kids not on social media/ your kid on social media Δ-3 happiness
other kids on social media/ your kid on social media Δ-10 happiness
other kids on social media/ your kid not not social media Δ-50 happiness
Maybe some form of co-ordination might be in the parents best interest... maybe some form of representative could do something about it if it's in the kids best interest?