Its not surprising. The fact is that sports athletes are so busy with training and playing that they have to leave their finances with friends and family and its those people that ends up getting them in trouble for no reason on their own. McAlister is a huge example, he invested in a car dealership and they pocketed all the money while not paying Wachovia the monthly dues. Rocket Ismail got screwed and Mushad Muhammed entertainment company was ran like Death Row Records.
For the most part, don't blame the athletes, blame their friends that scewed them out of their money. Most of the time, they end up on their feet because of their NFL pension and the fact that the businesses are usually incorporated protecting their personal assets
You left out that many athletes (and entertainers) adopt a lavish lifestyle that's predicated on a certain income level. When they retire, or, in the case of entertainers, are no longer hot, their income drops but the bills stay the same. Eventually, they go bust.