In California the public schools are funded mostly by the state with some additional money for wealthy districts grandfathered in. Still we have the disparity. Wealth districts have volunteer parents, fund raising, and voters willing to approve special bond issues. The poorer districts tend to be poorly run, wasting more money. They have less community support, fewer volunteers, etc., etc. There are individual schools in poorer districts that do extraordinary things, but usually it's the case of an extraordinary principal.