There is no money in education in China, at least not as a teacher/instructor/professor.

So, they end up having to accept more than their fair share of unqualified westerners for those jobs. And that's exactly as it should be. Mind you, even such greenhorn teachers tend to do a good job in spite of the mediocre pay. I think many westerners trying their hand at teaching here in China don't want their students to look down on them. So, they usually make a little effort to teach. But how well they are actually teaching is something else!