My paycheck for teaching one class during 10 weeks -- Tech was on the quarter system in those days -- was $400. For that amount I organized and delivered 20 lectures of 75 minutes each, graded homework, developed and administered and graded exams, helped students outside of class, etc. It worked out to around $8 per hour. At the time I was making the equivalent of $18 per hour as an engineer at a predecessor of Sprint. I didn't teach because I had to rely on the money.
Thirty years later, most universities depend on adjunct instructors for a significant amount of undergrad instruction. Adjuncts have no job security, few if any benefits, no say in how the universities are managed, and poor salaries. From what I can tell, adjunct salaries after adjusting for inflation are about the same as what I was paid. Of course, your typical university administrator or tenured professor is living high on the hog compared to 30 years ago, even after adjusting for inflation. Is this exploitation? That's one way of looking at it, I suppose. Another way of looking at it is simple supply-and-demand. Apparently there are many persons with post-grad degrees who are interested in teaching, so why shouldn't the universities pay as little as possible to hire and retain them?
If adjuncts are not happy about their compensation and terms of engagement but choose not to leave the profession, there is only one answer: