Kindergarten waiting lists are overflowing, and parents in the Big Apple don't know if their children will have any school next year, much less the program of their choice. The New York Times reports that families moving into new condominium buildings and parents trying to avoid private school tuition are flooding the public schools, with predictable results.
Enrollment growth raises a cost issue there that applies just as well in Kentucky. Adding one more child to a classroom with space has limited costs. Once the classrooms are full, though, breaking ground for new classrooms is hugely expensive. Ask folks in Boone County how that works, and they can give you a complete tour.
No discussion of school choice is serious unless it tackles this central supply problem. Private schools, charter schools, and schools with open enrollment will happily admit students right up until the last desk is taken. After that, they will cheerfully turn away all further applicants. When expanding "production" would cost more than they can charge, they simply will not expand.