I take for granted that urban centers subsidize rural areas

that's because it's in the DNA of empire to think this way. NYC does not produce any of the raw materials it needs to function. no metropolis does. many can't even maintain their own labor pool through social reproduction.

the metropole extracts resources and cheap labor from all over the world for pennies then facilitates their exchange for dollars.

America's "world class" cities are piles of wealth administered by landlords being waited upon by slumdwellers with guns pointed at their heads by the largest and most well kitted police forces in history.

these landlords only transfer enough wealth to the hinterland communities to facilitate resource extraction and portray this unequal exchange as their magnanimous charity, which they rescind on a whim... usually whenever these communities take steps to protect themselves from exploitation and toxic waste dumping.

every hollowed out and dismantled rural community generates more internal migration and downward pressure on urban wages while also reminding others of their place.

American empire is built on a network of mini empires. once you see the pattern, you'll see how thinking "cities subsidize rural communities" is the equivalent of saying "colonialism brings glory to the colonized".