That's the problem with vouchers - they are seldom used as anything other than:
1.) A way to subsidize the affluent.
2.) A way to further degrade public education, which is viewed as rabidly liberal by some conservatives.
3.) A way to subsidize religious instruction with state money, even going so far as to teach or avoid teaching established scientific principles.
4.) A means to make a profit through the sale of packaged educational material.

That isn't to say that some charter schools don't do very well. For every ACS, though, there seem to be at least a few Caesar Chavez Academies. If it's a crap shoot every time we open a new charter, why do we keep rolling the dice? If there's something wrong with our existing public schools, why do these people think opting out (effectively stealing resources from the community) is a better option than direct engagement?