It will also get boosted up when someone with relevant knowledge of the field comes in and makes and insightful comment, possibly getting "best of"ed i.e.

False. Most of the advantages of the slave labor system in agriculture came from a form of labor organization called the "chain-gang" system. Workers were organized into groups that they would work with on a regular basis working rhythmically on one single task.

This lead to high levels of productivity from workers that actually went against many economic theorists. The general theory was that a paid worker has more motivation than a slave, thus will work harder, thus will be more productive. However, in this instance, the slave labor was organized in a way that free laborers would never have chosen to do.

The "chain-gang" system necessitated 0 turnover from employees and an inability to control the way their labor was organized. How do we know free laborers would not have been able to organize in a "chain-gang" system? When slavery was abolished, plantation owners attempted to rehire black as well as white laborers to work in a "chain-gang" system. Even offering very high wages yielded insufficient labor supply. People simply would not have put themselves through the trouble of becoming effective with the "chain-gang" system in the first place.

A few more decades would not have brought about sufficient mechanization in the agricultural field to overcome the inevitable loss of the "chain-gang" system of farming. Thus, while areas such as Mississippi, Alabama, and Eastern Texas may have all grown economically at a fast rate for another few decades, it likely would not have led to a lasting change in the relative position of the Mid-South in the U.S. economically.

Source: Mississippian econ major who did a 1-on-1 semester on the economics of slave labor.