I think it's worth considering that the HN crowd probably is a selection of the population that skews heavily toward being self motivated and reasonably well adjusted. My siblings and I, too, had very unsupervised upbringings. We all would have done better with more structure. Not helicopter parenting, but some happy medium.

WRT unrestricted internet/device usage: porn addiction is a thing. So is gaming addiction. Adolescent girls being pressured to send nude photos to their classmates is also a thing. IMO parents should take reasonable measures to protect their children from the worst that is out there.