Earlier quoted context omitted.
Nope, I never said that. I am saying that the US was able to have the largest economy in the world by the turn of 20th century (before major international conflict) even despite an incredibly bloody civil war because of chattel slavery. Basically, in addition to how they stayed out of international conflict in WW1 and WW2, they had a big tail wind.
The slave economy of the Confederacy was literally burned to the ground by 1865. The legacy of that was poverty in the south.
Southern poverty stems from post-war wealth extraction by the same land-owning elites who dominated the pre-war economy.