Bureaucracies and their money are ultimately about funding the bureaucracy and not about fixing their area of responsibility. Vouchers threaten the bureaucracy and their suppliers, lobbyists, etc. Over time they become a powerful force against change.
They are the thoughtless souls who killed the goose that laid the golden eggs.
School vouchers have been under discussion for near forty years, yet they seem to be going nowhere beyond the pilot study stage. As long as The Regime (Congress, 0bama, bureaucrats, and some state legislatures in this case) can prevent them, vouchers will never go further, for neither the NEA nor Government Indoctrination Centers can stand the competition, and The Retime itself will never permit individual citizens to make their own decisions if it can find an excuse to intervene