This a response to John Flanary below who said:
"But I know a little about history, and I know that the cotton gin was invented in 1794, making harvesting substantially more effective and faster, leading to the real reason for increased harvesting numbers. So now I’m skeptical about even watching the documentary."
If you did know a little about history you'd know that "The most significant effect of the cotton gin, however, was the growth of slavery. While it was true that the cotton gin reduced the labor of removing seeds, it did not reduce the need for enslaved labor to grow and pick the cotton. "