> This was a gain that was achieved not by starting from scratch but by stealing lands from indigenous people

Seeing as how you are saying that the growth of America was dependent on 'stealing' land you must be implying that the success is dependent on the stealing of resources.

Which is trivially proven false by simply looking at South America.

> forcing Africans to work that land

Forcing Africans to work the land stunted American growth. It's not a coincidence that the richest parts of the countries are the ones that industrialized.