Purely anecdotal, but I was a tutor for two years out of college and planned to be a teacher (originally college, then high school). I went into a different field for 3 reasons:

1. Pay

2. Professionalism - all of the teachers I saw and talked to under 65 were treated like dirt, and were micromanaged instead of being treated like professionals

3. Barriers to entry. By the time I got my Master's and decided I'd rather teach high school than spend several more years getting a PhD, it was financially impractical for me to go back for more years to get a teaching degree. It was also very difficult to find internships and open positions. One guy I know who did a straight teaching degree interviewed almost a HUNDRED TIMES despite doing incredibly well in his program and student teaching at a prestigious high school.

I'm sure the kids are doing fine without me, but I had stellar reviews from every kid and parent I ever worked with, and from professors I TA'd for. People have told me my whole life I should be a teacher (came up again just the other day with the guy I was pair programming with). I'd happily take less money to be a teacher, but when you add in factors 3 and especially 2, it just isn't worth it to me. I'm not going to suffer a bunch of professional abuse and take a financial hit to boot to do something that my society doesn't seem to genuinely value.