I think the balance has to be established at the point where it becomes prohibitive. For example, is it actually damaging someone's future opportunities with how much more the financial cost is going to be? What you see is that if someone is working 25 hours a week, they're not going to have time to build those skills that are necessary to start a business when they graduate. A lot of things you learn in school are also the things that happen outside the classroom. If you're stuck flipping burgers or slinging coffee at Starbucks, you're not necessarily going to generate those particular skills required to start a business or generate the skills that a lot of law schools and medical schools and graduate schools require that you receive in order to get in.
So I think it is important that people should be able to devote their full time to studies, and ideally a university education is a full-time job, with everything that goes along with the education if you're going to be treated as a student and as a citizen.