The reason is simple and unprovocative. Pennsylvania controls and funds its educational system the way most states do. Government schools are funded primarily through local taxes.
State taxes provide most of the remaining funds.
Control is divided between state and local authorities. Thus, although most of the examples apply to Pennsylvania, they are equally instructive for policymakers in other states. According to a marketing survey conducted in 1993 by the Catholic Diocese of Pittsburgh, the biggest disadvantage of nongovernment schools cited by parents was cost. The 1997 tax credit law has not yet been tested in court.