In response to calls for universal preschool, E.D. Kain recommends vouchers:
[T]here is already a pretty solid system of private preschools and it would be enormously expensive to try to crowd these out with new public preschools. Since the infrastructure already exists, it makes more sense to give low-income families preschool vouchers to attend private preschools. It would be cheaper and it would result in less segregation by income.
The Dish 