The argument was about subsidies, which can be measured by looking at tax revenues and sources of funding. An esoteric argument about 'proximity to the city is

The argument was about subsidies, which can be measured by looking at tax revenues and sources of funding. An esoteric argument about 'proximity to the city is the source of all wealth' isn't well-defined or falsifiable. One could make the argument that Philly's proximity to NYC is the resource it uses to extract money, since NYC is much larger, wealthier, and relatively close.