> I have no idea how the teachers that are actually competent (they do exist) are able to stand it... maybe they can't and that's why.
Competent teachers get burned out very fast, or stick in due to an incredibly, incredible love of teaching. We lose many, however, who are more than good but just not psychologically prepared to be good teachers and constantly fight the school system.
I worked in US school IT for a while and I've seen all stages, from the engaged first-years, to the jaded but caring middle years, to the "I gave up a long time ago and only care about getting paid"s, to the lifers, some of whom still love to teach and some of whom seem to absolutely hate schoolchildren. Any teacher with >5 years experience in the US will tell you it's royally screwed up, but not many have the will to see past their daily grind and attempt any solution. And I can't blame them, given what they must deal with.