"you'll attract better teachers when you have 'better' students. For starters, the idea that every child should have a liberal arts high school education is insane."

Absolutely.

One of America's reigning delusions (and the premise of NCLB) is that all students have equal potential and innate ability, and if students don't do well, it is the fault of the teachers and the school. Few in the education establishment are willing to accept the conclusions of people who have devoted their lives to studying human intelligence because their findings are politically incorrect.

It is the quality of the students that determines how good the school is. If you dumped the Harvard students out of Harvard and replaced them with students from a community college, what would be the quality of Harvard's graduates?

I'm not a teacher, but from what I read, the quality of the average school has declined precipitously over the last 20 or 30 years because our reigning delusion requires, as you pointed out, that the dummy kids be forced into classes where they don't belong. Combine the anger and frustration of these kids with the pathology of the "bad kids" who shouldn't be in the school either, and I would guess that the daily work experience of most public school teachers is a nightmare.