Vouchers that immediately squander the social mobility provided by public schools by placing them in an opportunity to go into a financial death spiral the mome

Vouchers that immediately squander the social mobility provided by public schools by placing them in an opportunity to go into a financial death spiral the moment those who can afford to leave and take the tax money with them while those who don't have the opportunity jump ship to a public school are left high and dry in a local education system bleeding viability. Public schools exist as an egalitarian institution, why deliberately fracture them into pieces for any reason other than to kill the whole idea off? Tangentally the idea is often pushed underhandedly by some evangelical types to shovel taxpayer money into religious schools in a way that isn't currently legal to do outright, but that's a problem adjacent to the idea rather than the main problem with it.