Actually that's not generally true. Janitors at least work 12 months a year, many schoolteachers are paid ~9 despite being expected to work through them (on lesson prep &c).
It's possible to make low 6 figures, but a lot of pay is dependent upon length of time teaching and/or which district to get into. Good districts rarely have openings.
I'd say (not a teacher myself, but related to several) teaching is a lot more difficult than people give it credit for.
In my case that’s mathematics in academia so I’m going to be starving to death.