When I was growing up there were girls in my school who were friends because their moms were friends who has grown up together. There was one foursome whose moms were also a foursome. As a weird little shy immigrant, I found this almost awe inspiring. What happened is that people no longer have kids at a sustainable rate and the population is replaced by immigrants at a much faster rate, so society no longer has the cohesion and harmony to sustain the normal friendship lifecycle where you go through the stages of life and raise families together.