What you learn in college/university depends only on yourself. Tests are just the most convenient, unified way to measure students' progress. There are two ways

What you learn in college/university depends only on yourself. Tests are just the most convenient, unified way to measure students' progress. There are two ways you can beat tests: one is to train specifically for the test, the other is to actually know the subject. The first way is easier, but leaves you with little residual knowledge, and you don't even know how to apply that knowledge. The second way is much harder, and it requires work on your part. However, it pays off. Not only you get to pass the test, you're also now armed with useful knowledge. At my time in university, I've taken both approaches towards various subjects. For the algorithms class, I made a lot of effort to study and understand the subject. Today, I still have it in my head, and can apply it when needed. For differential equations, I just studied for the test. I don't remember anything now, and it's my fault for being lazy. I got an "A" in both subjects, by the way. What I'm trying to say is, the system is just fine as long as qualified professors are teaching. The problem is lazy students.