Salaries may be low, but total compensation is not. My mother was a grade-school teacher and complained that I made more right out of engineering school than she made after 25+ years of teaching. True, if you just looked at salaries, but she also (a) never paid into Social Security; (b) had a pension (which she is now drawing) worth 95% of her ending salary for the rest of her life, plus full medical. When I did the math and amortized her salary and all the bennies for a life expectancy of 80 years, she was pulling in ~$65K/year (I didn't even factor in the 3 month vacations).
I have a bro-in-law who recently retired at age 55 after teaching for thirty years in the public school system. He never worked summers. He doesn't believe in stocks and bonds, but he and my sister have plenty of dough even after spoiling their two now grown children.