pre Industrial Revolution cash crops have very little to do with America's modern wealth.
Seriously, the South's economy was so fucked by slavery-based agriculture and the persistent refusal to mechanize that it was only a matter of time before the whole thing either imploded or was forced to switch to industrial production methods. The latter was already underway by the time the Civil War rolled around - as in, slavery was
naturally on its way out the door, and would likely have entirely peacefully ceased to exist given more time, because it just wasn't as profitable as industrialized agriculture (which employs fewer, more skilled laborers, not throngs of untrained humans, and thus does not engender demand for a constant supply of fresh meat, so to speak).
The North won the Civil War in large part because of its massive industrial advantage, which meant it
wasn't using slave labor to prop up a large sector of its economy. The "white man" rendered slavery obsolete by technological means, then used said technological means to violently exterminate the practice of slavery not just in the United States, but in as many places around the globe as he could (thanks, Britain!). And he did it without taking credit for it on a racial basis. Yet these entitled black sons of bitches want to claim racial credit for building the USA. Not only are they dead wrong about the effect their labor had on the long-term development of the USA, but also they're horrendously culturally immature, in that they seem unable to simply embrace perceived forward progress without desperately clawing for race-based credit in the process.