Cherrybim, I’m not saying I agree 100% to this way of thinking, but I think I can argue somewhat plausibly that certain services and payments that are one’s communal “obligations” should be treated as progressive taxes and not commodities. American income tax structure is theoretically progressive on the whole – the more money you make the higher your tax percentage (bracket). The government understands that simply dividing the cost of running the nation equally by the number of (legal) residents or households is an extremely inequitable undertaking and, more importantly, can be unsustainable. Our society understands that government expenditures funded from tax money generally, eventually, benefit the country as a whole – thus, we have a progressive system.
The same might be said for tuition. Communal pressures, stigmas, and logic leave frum Jews little or no choice but to give their kids a Jewish day school education. No one will argue that mass Jewish education will at the very least spiritually benefit the Jewish community as a whole. Because of the obligation, one could possibly argue for modeling the school funding structure after our progressive income tax system.