There are simply too many English teachers who are not good enough at the language they are getting paid to teach. There is no way that someone who cannot comfortably talk and write about the most familiar topic, his/her daily duties, can produce students who can use English at a functional level.
But who is responsible for that? Whose fault is it that there are so many English-incompetent English teachers in the society? No doubt, those who are teaching university TEFL methodology courses are to blame -- partly, at least. Yes. That's us.