450 children multiplied by the $20,000 dollars (or more) that each child brings into the school district ( directly and indirectly) equals 9 MILLION dollars!
Follow the money!
If the services are that valuable to the family, then the parents do have a tough choice on their hands. But the schools do not receive the same compensation for ISP's as they do for IEP's. If a parent wants that type of level of service, they must attend the school full time.
Do districts provide therapy to illegal alien students?