The elephant in the room is that in American society, people are in general far more educated than they need to be. I have a bachelor's degree, none of the knowledge gained in pursuit of which[1] is of any help to me whatsoever in the course of my daily life, whether personally or professionally. And while I have no data, if the scuttlebutt is to be believed, I am very not alone in this. Furthermore, even a lot of the knowledge I gained in high school has proven completely useless to me[2]: outside of a class, I have never used any mathematics more advanced than the Pythagorean theorem.
As long as unreasonable academic credentials are required for jobs, though, there will be incentive for people to cheat—that is to say, cheating is not the problem; it's a symptom. Elminate the degree inflation in the job market, and you'll eliminate most of the cheating.
[1] Aside, possibly, from reading comprehension and writing skills, but those were not developed in college—I tested out of all the required English classes and all but one of the history classes—merely honed.
[2]The important words here are of course “to me.” I know lots of things which, objectively, are of no utilitarian use in my situation, but which I have sought out the knowledge of simply because it interested me; my enjoyment of them constitutes their usefulness.