Saving the taxpayer money by not using the state system is not the reason parents choose private school, but the fact of the matter is that it does save the taxpayer money.
As if it isn't, in the vast majority of cases, about buying or perpetuating privilege.
Or just trying to give their children the same great education that a few lucky people can access via the state by reason of their postcode. In some areas of the country, the only option to access a wide variety of subjects, great sports offerings or an academically challenging school is to pay for it. Some families can access that through the state, but very many can’t.