Frankly, (and no, I don't mean this as a flame bait, mods) I see it similar to when alcohol was introduced to the tribes of America, when they were genetically predisposed to both increased intoxication and addiction to alcohol; we introduced smartphones not only to a population that was simply not at all prepared for it psychologically (arguably, genetically too), but it was also introduced largely to the young through the adults, who were even more psychologically vulnerable to every single form of predation and things you would want to protect children from one could imagine.
I know people who suffer from both the effects of smartphones and "social media" (some both, some each) in several ways too broad in scope to detail here now (but it is very bad in many ways), even though the irony in one case in particular that comes to mind, is that it is due to secondary effects from their parents' behaviors, actions, and inactions related to social media and smartphones. To your point, the saddest part is that it is not the "bad parents have natural outcomes..." it is the "children" who are suffering and having to recover from even things like grooming and psychological conditioning, and having to "reparent" themselves following a young life of neglect and what can easily be described as abuse from it.
The challenge presents itself there that barring adults from "social media" and smartphones due to negligence, neglect, and various forms of abuse is a far more tricky issue and topic; especially when a double-digit trillion dollar industry is behind it that makes up what can be argued is the only remaining, functioning industry in America.
I will have to stop here. It has given me an idea for a book. Thank you for spurring that.