Failure is a pretty strong word, they all went on to do other things, better paid, they had options. They tried to teach, for a while, because they wanted to.

My point is just that they all underestimated how difficult controlling a pack of teenagers was going to be, even those who were at nice schools "with a PTA". That's what I think was meant by "babysitting" above (not my choice of word), it's a real hurdle. As you seem to agree.

I'm dubious that the world is short of video courses. But many people do miss out on human interactions which could show them other paths.