You are right to point out that such places don't exist. But it's worth remembering that the US was wealthy (and increasingly so) long before Keynes dressed up playground fairness as an academic discipline. Rich societies enable the existence of big government, not the other way around.
There is a strong consensus among economic historians that slavery didn't move the needle that much. Cotton production was perhaps 5% of GDP. The slave stock constituted perhaps 15% of national wealth.
