I agree with most of what you are saying. I get it. But what I'm saying is that the Type A students in this program who attack the problem and try to solve it (an approach that may be more suited to the business world) will naturally move on quickly. That portion of the program won't necessarily include all or even most of their recruits, but it will be a sizeable population.

Most good teachers "will constantly be revising...trying new methods". But not everyone works like that. Lots of people see things in a more finite way. They want to fix the problem and move on to the next one. We call people like this "decisive", in a take-charge kind of way that cuts through the bull. Teachers have to solve problems, but they need to take the long view. What works today won't necessarily work tomorrow, or next week, or next semester. The things you cite that make a good teacher are exactly what some people can't begin to cope with. Many teachers who burn out or drop out can't handle the constant revising and reevaluation of everything. They (and sometimes I) would see this as solving the same problem over and over. You start to feel like Sisyphus with the rock, never getting anywhere. Higher salaries would be great (and heaven knows they would make a huge difference to some), but I'd bet the repetitive aspects of the job are a big part of why some people can't spend their whole careers in teaching.