Don’t disagree on that point. At some time in the future, the soil would no longer support the volume of cotton production. Other sources of cotton were being developed in India, Egypt and Brazil. These sources would have competed with Southern cotton for the European business. The cotton economy was about a large as it was going to get in 1860. Whether the South would have become a manufacturing power house in a few years, is speculative. Lacking local sources of anthracite, iron ore and other raw material would have slowed the process. Very little inclination for skilled labor to move South because in all skilled trades, the worker had to compete against the slave. Almost every manufacturing operation in the South employed slave labor to some extent. At Tredegar Iron Works in Richmond, slaves made up 50% of the work force. Not only were slaves used for general labor, but they were skilled pattern makers, foundry men, millwrights, machinists etc. Throughout the South, slaves were employed as mason, carpenters, blacksmiths, cart wrights etc. Very difficult for a skilled tradesman to compete against slave labor in those trades. That to may have changed over time, but it would have a long time, IMO.
Not only were slaves used for general labor, but they were skilled pattern makers, foundry men, millwrights, machinists etc. Throughout the South, slaves were employed as mason, carpenters, blacksmiths, cart wrights etc. Which was exactly the situation in Europe regarding serfs during the Middle Ages. Eventually the land Lords realized that a serf produced many more goods if he worked for himself than he would if someone constantly compelled him to work. This is when a freedom movement occurred all across Europe.
This history is mentioned in some detail in the first chapter of this 1860 book.
You can tell it is a product of it's era, but the man (New Yorker Thomas Prentice Kettell) puts forth an Interesting way of looking at things.
I have little doubt his view was how a lot of people of that era saw things.