The plantation owners sold cotton for a profit, so they were financially incentivized to expand production to increase profit. They could get by making the same profit with fewer slaves, or they could use the same number of slaves to make more profit, and with more profits, they could buy more slaves and make even more profit.

The entire economy of the south quickly became dependent on the institution, as capital investment solely flowed into slave plantations, while the industrial sectors stagnated. It took the war to change that system, and turn investment towards industry.