One and done. As in one year of college and you make the leap to the NBA. For the NFL, it's three years and done. Either way, if you're the average pro athlete that was awesome in college you probably don't have a college degree. And even if you do have a degree, you most likely don't have any experience in the field you majored in because, well, you've been busy being a professional athlete.
Take a regular Joe Schmoe, say he got a degree as a chemical engineer, but he takes a job as a fitness trainer after college for five years and then he wants to finally go into engineering. On top of not having any experience, he's spent five years out of the loop and is not aware of the new advances in the industry. Good luck getting hired. The same goes for athletes, sure you have a degree but you have no experience—start at the bottom with an internship that pays little to nothing is a hard pill to swallow for someone that was recently making millions.