Most teachers are well meaning and hard working. However, they get ground down by the situation they are in. I know someone who teaches in an inner city school in Sacramento. She recently told me she does the "bare minimum." Why? Because even when she works her butt off, she doesn't get results. I don't think she knows how. She doesn't lack work ethic. She's relatively smart. She's well educated. But she's unhappy, and feels incredibly guilty about her situation.
Then tell her to quit, because she already technically has, instead of not contributing anything further she just gave up and no one is asking her to leave. That shit does not fly in most companies. Why should a teacher be allowed to just give up and still get paid?