> the real problem is they can't rule that parents must be responsible for their children

It's impossible for the average parent to police their child's smartphone. They just don't have, and never will have, the technical skills.

> I find the moral panic about kids with phones/internet access fascinating

And for those parents, which are quite rare, that do have the technical skills AND the involvement to ban smartphone usage at young ages, guess what. When Joey and Mickey and Sarah all have smartphones and are doom scrolling TikTok, even those parents lose. If all socializing moves to smartphones, the weirdo kids that don't have them or access to the "cool stuff" are automatically excluded. It's extremely alienating and nothing like not having calculators or PCs.

Back in your day (or mine), huge corporations more akin to drug dealers employing tens of psychologists weren't trying to get kids addicted to calculators.