It’s no secret. In recent years, there has been a growing concern over colleges and universities increasingly relying on adjunct professors to teach a large portion of their classes. According to some reports, roughly 75 percent of instructors teaching college-level classes in the U.S. are not on a tenure track and more than half of all faculty hires are part-time and paid next to nothing. One report found that nearly 25 percent of adjuncts rely on public assistance programs, with 40 percent unable to afford basic household expenses.
So, there are too many people around with PhDs who want to teach college.
The answer is to have fewer people doing PhDs. Go get some other job.