My son regularly mixes with younger kids, kids his age, older kids, Gen Zers, Millennials, Gen Xers and members of the Silent Generation (he’s a little low on Boomers for some reason).

That made me think of what friends I had in school. I almost never had actual good friends my age at any point in my life. I consider that age segregation a factor to why I was so weird and quiet in elementary school age especially. Even now, my two best friends are 11 years older and 11 years younger than me. School age, what I remember positively more than friends are adults who gave me the time of day and would treat me like a person. (definitely were not teachers) My cousin is middle school age and homeschooled and has more good friends around his age than I did that age by far, despite not being forced around them all the time. It happens organically. He's also basically a friend with me in a lot of ways as he's never had beaten into his head that friends should only have been born +- 6 months of him. Cramming kids in a group of people their age and not really ever being around anyone else is not social development at all, I'd argue it's socially stunting.