Private schools have to really educate their students. Public schools just have to take them in and see them out. Moreover, private schools have to compete against public schools that offer education for free. And that's not all. Private schools, and even home schooling, can only exist by government permission.
Government controls the licensing of all education.
The plain truth is that the government has a virtual monopoly on education. This is why parents feel impotent to prevent the disintegration they are witnessing in the schools and in their children's minds. Parents have no control. Public Education is a despicable monopoly that unfortunately was accepted by the American people as a good thing. But if Americans would just question this misguided belief, they might just glimpse that the answer to a better education lies in a free market where each parent has total control over their money and their own children's education.