WAY too many schools to buy the rights to
Couldn't be more wrong. Every school, by being a member of the NCAA, licenses their school out for use. That is why it is bad when EA has the exclusive license for the NCAA, which means another company could make an NCAA game but it would be one with made up school names.
The company just has to buy the rights to use ncaa schools. It's up to the game how many schools they want to put in