As learning became more prestigious, rich kids started going to universities as well. They were not there for vocational training. But they were the newcomers. The original model of university student was the one Westfall described in his excellent biography of Newton: "a plodding group, narrowly vocational in outlook, lower-class youths grimly intent on ecclesiastical preferment as the means to advancement."
If anyone wants to learn more about the origins of universities, I'd recommend Haskins's Rise of the Universities.