And they are very service-intensive (ESL, free lunch, latchkey, legal/regulatory, behavior, remediation, etc.)
It is a whole industry unto itself - something never even dreamed of when this country was founded. Here in NJ, it devours at least 2/3 of our highest-in-the-nation property taxes.
There is a reason Republicans wanted the SALT limits in the new tax code; socialist areas were basically subsidizing their programs with potential federal income tax dollars. That is also why the left was enraged by the limits.