That's because of the twisted market government has created. In the real world, most roads are built on taxpayers money and police is paid for using tax money of the very same people they beat up. But is this real world a place you want to live in? If I don't like how I myself or my children are being educated (protected, treated), I should be able to stop paying and go buy someone else's services immediately. Without that, the feedback loop is broken and the system stops working properly.
That's a fine bit of moralizing, but the reality is you have to illuminate a sane path from here to there. Most the paths I've seen proposed do not seem in the least bit viable.
In the real world most education is government subsidized, and the counterexamples that do well seem to run on a non-profit model.