Imagine a system of college education supported by high and growing government spending on elite private universities that mainly educate children of the wealthy and upper-middle class, and low and declining government spending on public universities that educate large numbers of children from the working class and the poor.
You can stop imagining. That’s the American system right now.
Government subsidies to elite private universities take the form of tax deductions for people who make charitable contributions to them. In economic terms a tax deduction is the same as government spending. It has to be made up by other taxpayers.