They are buying food and clothing. And it isn't just consumption, but also labor production I was pointing to. They do work, and many at jobs I wouldn't want to do.Poor America isn't the market: Poor America's GDP is $15k as compared to the $30k in government services received per capita. Barring individual level "deficit spending" (credit card debt, largely), those numbers indicate that they're not consuming to a great degree.
Rich America, for better or worse, are the consumers thanks to their incomes, which are admittedly based in large part on the cheap labor that Poor America provides.