Backup quarterbacks in the NFL is actually the worst possible example you could've given here. How many of those do you think they need relative to the population ? What level of play do you imagine they have to exhibit?

Unflagged remix yayy yayyyeee

The point is that even in the NFL, there's a wide and very visible gap between the top and bottom levels of quarterback play, and that's taking into account that these players (including the backups) are already considered the best of the best.

I only mentioned the NFL because I was riffing on your comment about throwing footballs, but agree that it's generally a stretched analogy. The extreme scarcity at the top of most professional sports and the resulting lack of utility/career viability outside of the big leagues doesn't compare well to most vocations.

The argument also assumes the only reason someone plays football is to play in the NFL. I invested significant time learning to skate because I enjoy it, not because I think I'll become a professional hockey player.

Backup NFL quarterback is a pretty damn elite job. There are what, 50 or 60 of them in the world? Vs dozens of NCAA div 1 starters who graduate every year.