I believe students are doing poorly because of low expectations.
I agree entirely. I have sat in lower learner classes and have been appalled at how teachers talk down to these students and the students, in reply, do not surprise the teachers. I met one teacher who came to the public school from an exclusive private one who told me she believed that she could get the same level of performance out of her public students--and she did. I saw the evidence--she got great work out of these middle-school students. But she was the only teacher I ever met who really believed it. What a pity and a waste.