How did it happen? Education in the US works on a freemium model.

The pay-to-win aspect is more obvious at the university level, but it occurs at K-12 too: it's just that there the cost is not directly charged by a school district, but occurs via the premium for housing in that district.

(take a null hypothesis: a world where school districts all offer the same education. Even in this case, should parents somehow agree on which the "good" district were, it would have a premium reflecting how much parents who care about education are willing to pay to live somewhere where their children's likely friends' parents also care about education. "the mother of Mencius chose a neighbourhood")