If the estimate of Dempster's net worth that I posted is anywhere near accurate, I don't see how we can say he needed the money that bad. And it's pretty clear he didn't have any lingering desire to play again, because his cleats stayed hung up.
700hitter has talked about how a lot of ballplayers blow their money after they leave the game. I'm sure that happened a lot in the old days, but in the days of big money, how many players who made a lot have done this?