I just started reading James McPherson's Battle Cry of Freedom, and he says that the South's economic practices amounted to (quoting a northerner), "to sell cotton in order to buy negroes - to make more cotton to by more negroes, 'ad infinitum'..." (p. 97), and that industrialization attempts in the South were - more or less - failed and pointless. Assuming Lincoln hadn't won the 1860 election, and the violence across the country hadn't escalated so much to that point, would the South have driven itself "out of business" with slavery?
McPhearson mentions on the same page that historians disagree on if it was a good economic practice for the South, but this is also a almost-30 year old book, so has any opinion changed on this? Or is the whole thing greatly oversimplifying the matter entirely?
I should start by saying that this question is fundamentally impossible to answer. There are all sorts of things that could "possibly" have happened. Instead I'm going to talk about how entrenched slavery was in the cultural and economic fabric of the antebellum south. From there we can perhaps talk about what was likely.
By 1860 slaves were the single most valuable asset in the United States, worth around $3.5 billion. That's more than all of the railroads and manufacturing combined. Worth even more than all of the land in the U.S. There were more millionaires in the Mississippi Valley alone than in than in anywhere else in the U.S.
Which is all to say that even if we can look back and see that the the industrialized north was becoming more productive, right up until its end slavery was a colossal source of wealth.
I think also that we should recognize that the economics of disruption (to borrow a modern term) is never as brutally logical as, "this model is more efficient, thus it will replace the old one". These changes are always made in specific political and social contexts. Change, especially radical broad-based change, needs to overcome social barriers, entrenched interests, and a whole host of other obstacles, even if it "makes more sense" than the status quo.
You can even see this in the history of the South in the run up to the Civil War. The South knew that their economic interests were increasingly diverging from those of the North. They felt very keenly that their culture and lifestyle was under threat. That is why they were pushing so aggressively to expand slaveholding lands. They pushed to create as many states and even supported pushes to expand slavery into Central America and the Caribbean (if you keep reading, I think McPherson makes this point extremely well).
Slavery was fundamental to the culture and society of the Antebellum South. Many (white) southerners believed that it was slavery that made democracy and equality (for white people) possible. Even the poorest white man wasn't black, and was thus an aristocrat.
We look back at slavery and, aside from the obviously horrifying moral angle, can decide that it didn't make sense. But in spite of that, there were no attempts by the South to move away from slavery. On the contrary, they fought as hard as they could (peacefully and otherwise) to preserve it. When slavery was no more, they fought to keep as much of white supremacy as they could in the form of sharecropping and Jim Crow. During the Civil Rights movement they fought to preserve that system as well.
Could slavery have ended on its own? Sure. But considering that hundreds of thousands of people died to preserve it, I don't think it ever would have.
Sources:
Battle Cry of Freedom, James McPherson