It’s because they’re not overloaded with administrators and administrator assistance and assistant to the assistance; and teacher assistance with assistance. And we’re not even talking about office staff with their assistants. I read where over half of a public schools money goes to staff payroll.
Public education, besides being a leftists propaganda machine, exist’s to provide jobs for incompetent diverse ones.
They also don’t have to provide a full time aid per special Ed student. A one to one ratio is expensive. I suspect most private schools don’t offer special education services? From what I’ve heard CMCS in Prinsburg, Mn is an exception.
Aids are, however, far less costly than administrators so you are correct about the biggest difference in expenses. School social workers, counselors, nurses, etc are further expenses.
Public schools have become a jobs program for liberals.
Nor do they have the “medical” staff of therapists - psychologists, behavior specialists, occupational therapists, special ed teachers, etc etc etc. plus one-to-one “shadow aides” for the pain in the ass students.