Those who can't send their children to local schools. What happens there depends on how bright they are, how hard they work and how committed their parents are to education. This is deeply ignorant. What happens when a smart kid is in the middle of a class filled with kids who have no interest in learning? Do you think the teacher will craft a whole special course specific to that kid? Or do you think the teacher will try to get something basic to stick at the lowest level, so almost all the kids get at least something from their education?
What happens when a kid's peers mock the kid for being a swot? How socially integrated is the kid going to be, when all his friends do things in the evenings, and the kid's stuck doing homework and study? Ever heard of peer pressure? Gangs? Do you have any memories of growing up in a state school in a poor area, of the risk of being beaten up if you venture into the wrong area, wearing the wrong uniform?