That's actually a myth since the 1860 Census showed that planters were actually transitioning their slaves over from the cotton and tobacco fields to the nascent industries, especially mining, that were beginning to take root in the South, about twenty or thirty years behind the North.
I think you misunderstood my point.
(1) Slavery was going to end because of growing moral concerns in the US and elsewhere. The South would have been forced, through diplomatic means and trade sanctions, to make that change. It would have been nice if John Brown and others had not so inflamed passions that people (e.g., Robt. E. Lee) felt that the morally correct choice was to defend their state (i.e., Country). Under the same circumstances, I may have made the same decision as General Lee.
(2) With the end of slavery, the South needed to adapt it’s labor intensive practices in favor of more mechanized processes. It doesn’t matter if it’s farming or mining or whatever.