For online courses it is no longer the case that exams are proctored in person. Most higher education in the United States is done at community colleges and regional state universities.

Once you have an online class with no proctored exams (or even biometric ID check) you don't know who took the class anyway. Frankly, that makes any "online degree" certification basically worthless without a proctored exit exam. That doesn't mean the education or study aren't valuable, they are to whoever is actually doing it.

I didn't realize that so many community colleges and state universities were basically online diploma mills.

A lot of colleges have become zombie colleges. Enrollment is way down. Gotta please the remaining clients.

Maybe the solution is to get rid of degrees and certifications, and just let the students who actually want to learn attend.

>And yet, the US has the highest density of renowned universities.

The renown has to do with a lot more than demonstrated ability of graduates.