the voucher idea would never pass as the goyim do not want to have to give up their free education. In effect, when you give vouchers to the families, they can choose whether or not to use them for public school or private. Many of them cannot afford to pay the difference between the cost and the voucher.
I hate to say it, but vouchers would not pass through the state government and if this idea of flooding the schools works, unfortunatly it would only help NYers and not the rest of the country. And there are plenty of frum schools around the country. We need to have a mass-country wide flooding of the public schools. If the gedolim would tell americans to all sign up for public schools in the same week-then that would make a real difference.