In some cases yes, in others no. A lot will depend upon his management of his money during his few top-earning years.
The well-trained scientist will have more career options at age 25 and will have grater earning potential from then on than the "average" washed out professional football player, especially one who never finished college. Look around and you'll see some rather sad stories out there.
But your washed up 25 year old former athlete is one of the illiterate ones who wouldn’t have gotten into college in the first place but for his God-given athletic ability. Probably would never have been hired to flip burgers otherwise.
So at least he had four good years and, yes, he’d probably be broke and not have enough $$$ to buy gas for the Mercedes, Ferraris, etc. that he blew his NFL salary on. Is he worse off for his NFL career? Other than having come to believe he walks on water and finding out ‘tain’t so?
I can’t remember now who it was, but last year a former pro athlete who dropped out of school to play had retired and went back to finish and get his degree. I’m thinking at Auburn. That was impressive.