Vouchers are not the answer to anything other than public funding for religious education. Vouchers would mean that the taxpayers would have to pay for duplicate school systems. The schmucks in the public school will be delighted because vouchers would enable them to claim that they can't be competitive when some/much/most of the tax revenue goes to the private schools.
No, vouchers will not improve general education but only the education of those who attend specific private schools many of which will provide religious indocrination, rather than education.
Let's ASSUME for a minute that you're correct and everyone is hoodwinked into sending their children to "religious indoctrination centers". Besides harmful lessons from the Bible, what else might they learn? How about cutting edge courses on homosexuality? Sorry, only available at public schools. PC courses emphasizing multiculturalism? Watered down "new" math and science? "Whole language" reading? Revisionist history? I'm beginning to see your point. None of these will be offered at the "religious indoctrination centers."