I don't know about the humanities, but up to about 2009 with a PhD in the sciences from a second-tier institution you could get a tenure-track job at another second-tier university or four-year college. That was the typical career track, because industry recruits only from top institutions at PhD level.

Then the funding crisis struck, and while universities are increasing enrollment (with the students shooting mostly for pre-med at my state school) they are no longer hiring for tenure-track positions, it's now untenured lecturers or part-time adjuncts.

Universities have found out that they can hire at lower salary levels because of plentiful supply, and they do not mind that quality of instruction is suffering. It is suffering because as a lecturer you are moving around every three years looking for a better deal and the first year is spent getting used to the syllabus at the new place, and if you are teaching three sections at three different places to make ends meet as an adjunct you just can't be good.

It's strange that the students don't mind that they are getting less of an education, but they really don't mind.