I think the rule is worded really badly in a way that makes it more confusing that it needs to be.
As for the rule itself, my table usually hand waves it and lets you cast whatever you want with your bonus action and action, provided you have the slots to do it. We haven’t had any issues with that feeling game breaking for us yet.
Paying them with an education is a good start, but it’s a pittance compared to the amount of money they are bringing in for other people. Arguing that their education is the only compensation they should be getting is akin to saying “we don’t need to pay the staff at our restaurant because we give them a free lunch during their shift.”
I don’t know what the answer is, but continuing to just offer them a scholarship while the adults in charge make money off their labor definitely isn’t it.