I've never understood the argument that teachers are underpaid. On the whole, teachers are smart, capable people who know what they are signing up for. Most are capable enough to get other better-paying careers, but chose to teach instead.

Even within education, professors at private universities get paid pretty well. There is more competition for those jobs and they require more schooling, but a smart teacher can choose to take that route.

I cannot think of any other career where we have this type of debate.