We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
Adjunct Faculty started as a way to bring in engineers and scientists from industry to teach a specialized course. Often this was part of a broader collaboration with companies so the actual pay didn't matter much. Now it is a way to handle enrollment swings without affecting permanent faculty. In my business I hire independent consultants all the time for both specialized and high demand work. Their pay is good.
University adjunct pay is driven by the hopes and dreams of people wanting the life of tenured staff. It is a temporary budget saver for schools. Having a significant portion of your catalog taught by people just getting by is never sustainable. Either they are well qualified and should be paid well (even if only part time) to retain them over the long term, or you are sadly abusing professional employees.
Universities need a thorough bureaucracy-cleaning. The cost per student has skyrocketed, enormously well over the general rate of inflation, over the past 50 years. All of this gigantic cost increase id due to "administration", not "teaching". In some universities, over half of the course load is taught by adjuncts being exploited by "administrators", who make hundreds of thousands per year salaries. It is an enormous scandal, exploitation and distortion of the purpose of universities. Instead of teaching and professors and scholarly departments being paramount, the administrative bureaucrats have enslaved faculty and arrogated control and funding to benefit themselves.
The government funding agencies and education department should issue guidelines to eliminate government paying for bureaucratic overhead above that from that of say, 1960.
It is already a federal gov't mandate. Go to your local public university library and ask to see the budget that includes faculty salary. If they don't have it ask where it is kept so that you can see it. If they receive federal funding they have to have it available.
The problem is the teacher's union, whether or not your school is unionized. Once we started demanding that women and minorities had to have extra points for the employment process, then we decided not to demand students reach a certain level of accomplishment the road toward low paying substitute faculty was paved. Unfortunately, the solution really was what a tenured professor did during the past five years to add to the wisdom of his field. When that was the gold standard more faculty did the evening/weekend home study necessary to stay in the lead in their field. Today's single mother with a 3rd tier Master's degree is neither a scholar, nor a professor. Her part time salary is merely intended to help her support "HER" family. But, then again we don't believe in integrity, ethics, etc. anymore. The hippie generation destroyed that--too cumbersome.
In many states, university salaries are published online through "transparency" sites these days. Often is is part of a larger site focused on all public employees in the state. In other states, though, often newspapers or other publications will publish them as a result of freedom of information act requests. It's not difficult to find the information in most states, though a few states (usually "blue" states, surprise, surprise) resist putting too much information out there.
As far as the adjunct situation, in many fields, PhDs need to ask themselves whether or not they are willing to do that work and, if so, for how long. For me it never seemed worth doing because I could find other kinds of work that paid better without the frustrations and long hours that can come with teaching.
The objective value of what these adjuncts teach can be inferred from the fact that none have tried to produce the content independently and therefore escape the villienage of the university. What they teach apparently only has market value when linked to the magic parchment.
I suppose ironically, we are in a far less intellectually curious period than the early 19th century industrial revolution. As people flocked to the cities for those "horrible" factory jobs, they also supported a large offering of lectures in the evenings.