Its a problem of incentives. For many courses the psets make up a large chunk of your grade. Grades determine your suitability for graduate school, internships, jobs, etc. So if your final goal is one of those then you are highly incentivized to get high grades, not necessarily to learn the material.
I think you somewhat touched upon what I believe is the root of the problem:
> highly incentivized to get high grades, not necessarily to learn the material
Based on my own experiences and observations, I think grading is a far larger issue than cheating. I am not convinced that good grades are necessarily reflective of enrichment nor how much material has been learned. If a person makes the a high grade in a particular class, what does that actually mean?
I made high grades in plenty of classes that I couldn't tell you anything about what I actually learned.
>Based on my own experiences and observations, I think grading is a far larger issue than cheating. I am not convinced that good grades are necessarily reflective of enrichment nor how much material has been learned. If a person makes the a high grade in a particular class, what does that actually mean?
Exactly. Grades and learning have become decoupled.