Your solution: keep as the primary practical option government schools that are absolutely controlled by centralized government bureaucrats, and that indoctrinate students and provide a shitty education.
Voucher sulution: return local citizen influence to local public schools by giving parents a direct choice that will force government schools to adapt to the educational needs of those they serve, rather than dictate to those they serve what their needs must be.
It has nothing to do with practical. It has to do with "can afford".
Oh no, some people can't afford what others can! This looks like a job for Compassionate Conservative Man!