You don't seem to be understanding the importance and effect of selection criteria bias.

Much of the personality and intelligence is genetic and that's determined at conception, as for optimum parenting it seems that general indifference yields the best outcomes. There are many ways to damage a person so they won't reach their potential but there does not seem to be many ways to 'make' a person better than they otherwise would have been if they were largely left alone to control their own lives.

Understandably parents want to feel more important and in control, and that their investments will yield good results. And since most people want to feel this way they like to promote messages that reinforce these priors, so the whole platform slowly turns into Linked-In.

I base my assessments on large scale machine learned behavioral analytics done on a full click log history on a non-trivial portion of the US population. Unfortunately I know things about society that I really wish I didn't.