It is easier to destroy than to create. If successful, De Blasio may well destroy NYC public schools' oases of excellence. Some parents will shift to private schools. Others will move.
He will destroy the gifted schools and that will cause the regular schools to rot further. It will not help them to gget the smart kids back in the dodo schools. They will get bored or do their own thing outside of class and still top the A and AB lists until that must be dealt with, too, by the egalitarians.