Your logic has several flaws.
If the new NBA rule requires a kid to go to college for a year, he will likely go to one where he can play immediately as a freshman and have a big impact so he can solidify his NBA stock. It is very rare that a freshman has that big of an impact at a BCS school. Yes, I know there are a couple freshmen at KU that have had a big year, but nationwide, there are extremely few others. So it might take a few years, but some super-preps might eventually learn that they can play a lot more by going to a mid-major school and impressing the NBA scouts right away.
Even if they don't go to midmajors, more of them might go to the prep schools that have popped up in large numbers and skip college totally. That hurts the BCS schools more than helps them.
And instead of going right to the NBA out of high school, these superstar preps will only be going to college for 1 year, so how much will that disrupt these top programs. A number of coaches at top programs have already spoken out about how this turnover hurts their team's ability to develop. Some BCS coaches have even said they might avoid these kinds of one-and-done players because it doesn't help their programs. It will be the mid-major schools that will have the senior lead teams that might give them the chance to compete evenly with these BCS schools that are constantly turning over.
Already, more than ever, the top prep players want to play for Kansas, North Carolina, Duke, etc, so they can be on Sports Center every night. Yet the mid majors have remained competetive. And in the case of the MVC have even gotten better. The Mid-major MVC is rated ahead of the major Pac 10, CUSA, Atlantic 10, and Mountain West, and about even with the legendary Big XII without getting all that talent the BCS schools get. Somehow, I think the Midmajors will find a way to remain competetive.
