If the government schools were producing graduates with marketable skills, disciplined work ethics, and a broad knowledge of science, art, history and philosophy, there would still be a case for school choice, because in our diverse society, many parents are compelled to let the government educate and even indoctrinate their children in ways they do not approve of. The extreme historical example was taking away the children of American Indians and putting them in boarding schools where they were made to abandon their native language and culture. School choice was deliberately rejected in order to create a uniform indoctrination of the values of the authorities. In the United States, parents do have the option of sending children to private schools, and several hundred thousand students are being taught at home.
School choice provides a level financial field.
The two main approaches are vouchers or tax credits, which can be used for any school, or the more radical policy of no government funding of schools, but with financial assistance for poor folk who can't afford tuition. School choice within the government sector has also been proposed and implemented in a few places, but that leaves schooling as a government monopoly, without complete free choice. Critics of private schools claim that education is a public good which should be provided by government to ensure equality and good citizenship. There is a public benefit to subsidized schooling, and it shows up in increased land values near the better schools. But we seldom hear these government schooling advocates proposing to tax the rents generated by this public good.