I disagree.
#1 I think social media should continue anonymous. In cases of criminal activity tracing via IP addresses can be performed.
Prohibition should have taught people something but apparently did not. People will find a way. It is absurd and counterproductive to attempt to control people when there are so many ways to circumvent. Are you going to require retina scans to access social media with a need to re-authenticate every 5 minutes?
When you forbid something you make it attractive. Kids can gain access to porn easily & do. That eliminates your analogy. The porn laws are on the books so that the adults allowing access or distributing can be held accountable and punished. No one believes the laws make it impossible for kids to access porn.
It is the job of the parents to educate their kids about using social media, to monitor and to block when appropriate. No one can or should try to substitute for the parents. I can scarcely believe you would trust the Government or the social media companies to protect your children. Giving those entities more power is anathema and should be avoided at all costs. Not only would the purported aims not be achieved, the way that power would be used is beyond the imaginings of a moral and sheltered individual. Big Brother is here today.
Even after prohibition alcohol is still illegal for minors. Not sure how what you stated supports your premise.
If anything it shows that some restrictions are used, we can debate the effectiveness, is your point alcohol show not be banned at all, minors should have complete access to it?
And yes the porn laws do just that, make it so adults can hold other adults accountable, now why would that not work for social media?
My preferred approach would be to see the internet finally divided into extensions to allow at more effective controls and blocks of material inappropriate for minors.
I am absolutely not for loss of privacy, with the interment though, unless you are on a library desktop, logged in through a tor browser and in a ski mask (most libraries have cameras now) you are not anon. Your ISP knows and will give all your information up in a heart beat.
Also anyone who thinks these company VPNs provide anonymity are delusional.