ZD: You seem to have zero faith in Democracy and fairness. I’ll address fairness first.
The dollar amount given by the state is based mainly on the number of public school kids. It’s a no brainer that the state should take into consideration the number of private school kids when calculating funding. Unlike what you are trying to portray, kids going to private school are actually saving money for the state and township — they’re not the ones draining the pot, except that the pot is too small to begin with.
Now back to politics: Hopefully some Legislators can simply be swayed by the fairness argument, while other probably rich districts will also gain by including all kids in the calculations for a fair funding formula. (Unless there’s some income test built into the law.)
Now “pork” is definitely built into many laws, but it’s not always the case (not everybody is corrupt) many vote according to party lines, and it doesn’t have to be wrapped into that same law. Politicians can be very patient, favors and promises are exchanged — so yes one hand washes the other — but it’s not so transparent or immediate. According to your logic virtually no laws can be passed, no bridges can be built etc., as there are always those that benefit less than others who will stop everything in its track. (This frozen state is more applicable to the federal government nowadays.)