Even if there were more ways to "vote with your wallet" is abundantly clear that a lot of parents, respectively, (a) couldn't care less anyway, and (b) can't actually tell a good charter or voucher school from a bad one.

When the purpose of schooling is ensuring a civic floor amongst citizens the effectiveness of things like the home school co-ops mentioned can't come at the expense of population at large unless we wish to surrender the republican form of government for something else.