There are two sides to a price calculation - the supply and the demand side. The price for teaching is low because the supply is huge - there is a vast pool of people who want to teach literature, and are willing to do it at very low prices. If a literature adjunct quits, the college can immediately go to the waiting list and find someone else willing to take the job for $5k/class.
In contrast, if I (a programmer) were to quit, my company could probably not find someone willing to take the job for $35k/year.
It would be very shortsighted if society overpaid for college teachers, just as it would be shortsighted if they overpaid for military contractors or the stock of bankrupt automakers.
I wasn't referring to pay as evidence society doesn't want to pay for art, culture, education, etc. The low pay is one consequence of this fact. There is definitely an oversupply of teachers in the humanities and sciences. But it is true that funding levels per student are decreasing and that there is increasing pressure to 'streamline' the process. This is a buzz word for cutting out the unimportant stuff like art, music, etc. It's bad for society in the long run.
You are making some broad generalizations and it doesn't exactly work like. Replacing any programmer is just as easy as replacing as replacing any adjunct. Replacing a specialist scholar is just as hard as replacing your special programmer. Adjuncts are Luke your basic php programmer. Thye know just enough to get the job done. But a university chair is like an architect, you don't give just anyone that job.
In contrast, if I (a programmer) were to quit, my company could probably not find someone willing to take the job for $35k/year.
It would be very shortsighted if society overpaid for college teachers, just as it would be shortsighted if they overpaid for military contractors or the stock of bankrupt automakers.