> Also adjusted for purchasing power, they exceed $50,000 in Mississippi, America’s poorest state—higher than in France. Damn...how does a country get so rich?
Also, navigable waterways. Transporting goods by water costs 1/100th what it costs to transport over land. After the US established a corp of engineers to dredge our waterways to make them passable, the ability to transport goods increased substantially, making internal trade extremely cheap.