This isn't strictly true. As long as the NBA won't allow 18 year olds into the league fresh out of high school, these kids are forced to look at other options. College ball is a lot better vetted than international leagues to date. That might change in the future, but for now they are herded into college whether they want a degree or not.
Now, I agree with you on the benefits of a degree and the fact that they get to have one without needing to pay for it is amazing. But that's a different discussion.