I think it has been prevalent for quite a while now. I'm quite sure most people that become teachers don't become teachers for the sake of money, but you really can't survive too well when your start-out pay is about the same as that of a lower-end construction worker. Yet, most of the new teachers quit by their ~2nd year (being able to get tenure takes more than 2 years.) To even see a reasonable amount of increase, you'll need to get a masters and lots and lots of hours of teaching both inside and outside of school and hope that you don't get put into a permanent substitute teacher position (even lower pay and not as much benefits as a regular teacher.)
Having a small pay compared to most B.A/Masters degree and compounding the amount of work needed to become a "good" teacher, the only worth to it all is being able to raise the next generation.
The tenure system is also part of the problem. It was originally a college system because their protection was pretty low relative to a teacher in the k-12. The college had the ability to kick a great professor for a low cost one just to balance the budget. If you were to kick a professor back in the day, it was generally considered "oh well" by the people doing the kicking, but in the case of k-12... the tenure system is a mass of chaos. Once tenure was brought into k-12... things got really iffy, as yes, some people do abuse the tenure system.
Quite frankly, a disrespect to the professors/teachers is a disrespect to the students. And I much rather value a professor over a businessman that rams the economy down the drain for their money.