>>81568132 (OP)People are products of their environment, genetics forms the foundation.
Most normal people don't reach the point of that picture and start families anyway. Even including the involvement of sports teams is kind of a far-fetched thing since all those teams have a limited number of slots. It assumes all the normal people in the world play sports and get women when most of the world has only gotten more secluded over the years. We've even got kids so sick of it all they turn weapons on the schools.
Normal people are more often disenfranchised with how life works and end up in unhappy marriages or cycle through relationships trying to make something picturesque like that happen. Even the normal people are fuck-ups, socialized fuck-ups, but still fuck-ups. People only become genetic dead-ends when their environment turns them so.
Chad can get ran over by a bulldozer before he hits puberty and that would make him a genetic dead-end. It is quite literally all luck, and you need a lot of it to end up in a healthy relationship which gives way to healthy kids that hopefully aren't also ran over by bulldozers.