There ARE flaws in public schools, and I agree that school choice would solve part of the problem, especially for children who have parents who would be concerned enough to put their children in better schools.
You have to understand though, that part of the problem, especially in inner-city schools, is children with no home life to speak of. It's very difficult to teach a room full of kids who have no discipline whatsoever. To a great extent, schools reflect the culture of the community - where the community is falling apart, the schools likely are too.