I don't think it was that long ago that communities of humans were quite small, and the number of peers your age around you would easily fall into the 20-750 range.
Those communities did still suffer from the social ills being described. Personally I agree, having the freedom to 'reset' my group of peers every 3-4 years through to uni ended up being pretty valuable in making me a better, more open minded and more creative person than I might've been otherwise.