No offence...

Uh, because there were very few big plantation owners. Here's a quick summary of the Southern economy, and the relevant part: "Because large slaveholders owned most of the region’s slaves, wealth was more stratified than in the North. In the Deep South, the middle class held a relatively small proportion of the region’s property, while wealthy planters owned a very significant portion of the productive lands and slave labor. In 1850, 17 percent of the farming population held two-thirds of all acres in the rich cotton-growing regions of the South."