Have you ever thought to ask those teachers how much they make, and what their expenses are?
No, I've never done that because that would be rude. It's not my place to judge them. Of the one with whom I had a personal relationship, I know he had a child with greater-than-average medical needs. The others seemed to signal that they were just trying to make some extra money.
I don't know where you live, but in my state, the average teacher salary is ~$50,000/year (source). I wouldn't exactly call that rolling in dough, especially when you consider that many have a master's degree and also have their own kids to take care of. Also, our budgets for resources and supplies is garbage in this state. Many teachers ask for donations of paper, glue, etc from the parents. Many end up buying the stuff they don't get with money out of their own pockets (so that employee discount helps). The problem just magnifies when you get to poorer school districts.