That won't leave enough money in the system for the students with special needs. They are very expensive to educate. Public education is efficient because of economies of scale. The average cost per pupil includes the special needs students, the students who don't speak English as a first language, and the students who need all sorts of social services. Spilt it all up into separate private entities and watch the costs skyrocket. The private schools we outsource our neediest students to are 80-240k per year. If we sent out all of our kids with special needs, our costs would triple, at least. Charter schools seem cheap because they cherry-pick the kids who don't have special needs, behaviors, or social support needs.