My taxes in Great Neck aren't as bad as they might be, certainly less than it would have cost to pay for three kids times four years at private school. The key to the success rates at GNS have as much to do with the culture of valuing education as with the money in the district. There are other problems (some kids with way too much, balkanization by the students from 8th grade on) but a truly world class education can be had here.
It is a "tribal" community after all (per a grad school classmate of mine from Great Neck who was MOT).
Kids tend to segregate themselves from 8th Grade through college. When they get into the "real world" (depending on what profession they enter, of course) they realize they can't segregate themselves as much as they used to.