The Market Revolution truly transformed the economy of the North. By contrast, its impact on the South was less pervasive. It is said to have brought about the boom in cotton, but it did not fundamentally change the way the economy worked.
In the North, the Market Revolution brought about a decline in subsistence agriculture. Instead of working on family farms that were self-sufficient (or nearly so) people started to work on farms that grew crops to sell. Many people even left farms to work in the factories that were springing up around the North. This created a situation where the North developed a diverse economy that was based on the market system where it had previously had an economy that depended on small practitioners of subsistence farming.
By contrast, the South’s economy was not so drastically changed. The South’s economy had never been dominated by small subsistence farmers. Its dominant power was the plantations. The Market Revolution, in the form of Whitney’s cotton gin, did change the dominant crop in the South. It also ensured that slavery would boom as cotton was able to spread across the South. However, it did not create a diverse economy as in the North. The South was dominated by plantations before the Market Revolution and continued to be dominated by plantations after the revolution.
The Market Revolution, therefore, helped the North become modernized and industrialized but did not do the same for the South.