I don't think they could ever do that, and really, I wouldn't be surprised if someone challenged the draft system as it is because it denies the person a right to make a living. There is no reason to go to school, except for what parents see as the social aspects of being at a school and being in a controlled environment as the kids first time out of the house. But besides that, it really doesn't make much sense financially nor career-wise for the athlete. Teams will pay for college later if the person chooses to go. What would be a big positive and a good way for parents and players to stay happy, and for teams to sign HS guys easier would be to have a graduate school trust, just the same as leagues do undergrad. Then the general public would stop complaining about HS guys going pro because now all of a sudden they're able to achieve not only their bachelors, but also their masters degree, if they are so motivated.
But for a HS kid, extra strange circumstances aside, to pass up going the in draft and signing, he better be damn sure that he gets better at college because he needs to go a few rounds higher in order to make the same money. And for his career, he's already lost the training that he could have had. So coming out of HS, what he could have accomplished by the time he was 21, now he must wait until he's 24. That's a big financial difference. The only time that I don't see it fit for a HS kid to come out is if he doesn't make enough money to justify the risk of being released when he would otherwise still have NCAA eligibility. And that is not because of any real financial or career mistake -- just the love of playing whatever sport competitively could not be fulfilled.
Each player also needs to really look at 'will I improve?' at college and I think the answer is 'no' a lot of the time. Not versus the improvements that they could make at the pro level. In basketball, college seems to be so much about learning the system and learning to play within the system and not about just becoming a better student of the game. Football is kind of different because of the huge physical requirements that are not often reached with HS kids. Baseball at college doesn't mean getting better, either, as coaches need someone to step in and produce right away and win right away so a lot of guys get thrown by the side who have the tools but don't know how to play right away.
