It’s clear that there’s been a long term decline in mental well-being over the past few decades. In another example, men have far fewer friends today than even 30 years ago: https://www.americansurveycenter.org/why-mens-social-circles...

You can blame technology to a degree, but even then technology probably just serves to amplify existing negative trends. Kids today are far more likely than in the past to move around and have divorced parents. They’re less likely to live in inter-generational households. They’re less likely to have a job or go to church or interact with society at large in meaningful ways.

Meanwhile what fills that vacuum of civil society is other children, through age-segregated schooling and, these days, social media. That strikes me as a huge problem, because children are antisocial semi-humans without fully developed brains. Having children spend most of their time around other children, without strong socializing forces, is a perverse arrangement.