My 2 personal theories:

1. Money. Star players usually make a ton of money, and if they’re wise with it, they’ll never have to work again and pass their wealth to their children, and so on. Guys who know the game but where never athletically gifted enough to make it to the pros or make a name for themselves in the pros seem more likely to turn to coaching as a profession, since it offers them a chance to be involved with the sport they love while still making a good income.
2. It’s an entirely different skillset. Leading people is not the same as performing on the field. There are plenty of talented players that aren’t team captains for a reason. Sure, they can catch a ball and run routes, but can they lead a group of people? If not, they’re not cut out for coaching.

You know… I never thought about it. After reading this, I still don’t think I will.

For a league with as much parity as the NFL, it’s actually crazy that a team can go over 50 years without winning a title.

Not just the Falcons, but other teams as well.