shrug perverse incentives. For a lot of college students, the actual learning or lack thereof, while still important, does not affect them directly. But getting a bad grade does. Drop in average grade might affect their scholarships, various arrangements with their families and possibly future employment prospects. So while not learning the material properly is bad in a somewhat abstract and theoretical way, getting a bad grade might have a very practical adverse effect. And I am not even going to mention the social stigma of getting bad grades.

So yeah, getting a good grade is more important than actually learning and let's be honest, cheating is a more energy efficient way of getting good grades.