A big part of it may be that once you fall below a certain percentage of the federal poverty level, you start getting assistance. WIC kicks in pretty early, as do ACA assistance and Medicaid/CHIP.

And percentage can be anything below 400% of the poverty level, and the poverty level goes up with each kid - 400% of the poverty level for a family of 8 is $216k. https://snapeligibilitycalculator.com/fpl-calculator/