Luckily for one-and-done players, their chosen profession doesn't require a degree. It only requires 1 year outside of high school. Apparently the NBA believes there's enough value for them to earn those credentials in one year. I assume the kids going straight from high school did not provide that value, which is why they changed the rule. I also think many of these guys learn a great deal in their one year that benefits them at the next level. It's a good step between living at home where you've always lived and living on your own with all the vices the NBA lifestyle has to offer. I also think the college game allows them to learn how to play with other quality players (especially at UK and Duke), how to deal with the media, about time management, etc.
I don't prefer the one-and-done rule, but I understand it. Considering the short length of careers in professional sport, the risk of injury, the risk of flaws in their game being exposed, and the background of many of these players, I can't begrudge kids for leaving early. The discussion in the 30 for 30 about Dajuan Wagner is the perfect example.
I know many here may not judge the players but judge the schools, as if most of major college athletics isn't already exploiting the kids. I don't mind it as long as they do right by the kids and the university. In my mind, UK has done this well.