I'm reading How Europe Underdeveloped Africa right now, and Rodney offers that the inherent opportunity for sabotage in more advanced machinery means transitioning beyond a certain stage in development requires "free" workers, that slaves require high degrees of surveillance and are limited to using tools that are hard to destroy.
This is a convincing argument to me for why a transition away from slavery has a material requirement for free workers under capitalism when it comes to factories, but there was still (and is still) a ton of labour that is ultimately performed without advanced machinery, principally agriculture.
I suppose my question is, wouldn't a maximally beneficial set-up for the bourgeoisie have been one in which the cities had free worlers, but the countryside still was allowed slaves to pick oranges etc? (I do know that most agricultural labour has been replaced by complex, easily sabotage-able machinery now, but that was not true in the 19th century)
(and if anyone has any recommended reading on the topic that's appreciated too)
In addition to the other good answers, there may be a couple other explanations that work alongside those mentioned. In the time before the war, there was discussion about whether slavery would eventually be phased out. And it certainly would have eventually. However, just because something may appear to be more profitable (wage labor), it's something else entirely to convince one economic class (slavers) to completely upend their entire mode of production instantaneously. The costs to transition over to wage labor would likely have been high and very disruptive. There's a contradiction in capitalism in maximizing short versus long term profits; and I think it's generally true that given a choice, capitalists will take $1.00 now over $2.00 tomorrow.