“First-string stars make millions. The grunts make a few hundred K, and are replaced within a year or two with younger players unless they show promise of becoming a star.”
If they only play a few years why do they deserve a pension?
They don't.
There are a number of young men, disproportionately black, who think they will get rich is professional sports. They spend their high school and college years focused on sports, instead of actually getting an education.
Most are not picked for pro teams. Of the ones who are picked, most don't get retained for more than a few years.
So there they are, in their 20's, no education, no marketable skills, and the money soon runs out. There is no cure for being stupid.
If anybody in the league actually cared about them, then they would convince the new players to put the bulk of their salaries into an investment account, and only touch the earnings, and never the principle. But they don't.
Because they don’t want to grow up.