The problem is that anyone can qualify for a student loan regardless of their ability or future ability to pay. Students are also conditioned to believe that they should not let the cost of going to college prevent them from attending any specific college. Both of these factors prevent colleges from even attempting to keep costs and expenses down.
Colleges also have the incentive to offer worthless degrees that offer little to no job skills, but appeal to the masses as the more people that attend a college the more money the college will receive.
Colleges have little to no incentive to keep costs in line with what they should be and spend an ginormous amount of money on things like research. It is great that research can be done, however it is unfair for students to be asked to pay for this.
AFAIK the average class at college for "in state" tuition is closer to $1,000 per class for a 3 hour per week class per 12 week semester. If a professor is available for 3 hours per week per class they teach then each 3 hour class would have them work 72 hours per class over the course of 12 weeks. This works out to $13.88 per student per hour. If a professor taught a very small class of 20 students (most classes have attendance in the hundreds) then the school would be bringing in roughly $277.77 per hour that the professor works.