The classic argument "we can just make slavery efficient with capitalism"
Very valid argument,
It is consistent with what many economic historians like Robert Fogel and Stanley explored in Time on the Crossroads (dont remember full name) though they controversially argued slavery was still profitable without much substance unlike Eric Foner, would point out that slavery was deeply embedded in the Southern economy and culture, and not likely to end purely through market forces
My point still stands, factories require skilled, flexible labor and strict time discipline. Slaves were not ideally suited for this environment, especially when compared to free wage laborers who could be hired and fired. We imagine slaves as modern worker (who has been trained and educated by the government for 14-20 years in schooling) without any human rights, which is in fact not slave. So not profitable to use an actual slave in factories and trust them to use expensive machines too.
Another mark is that Industrial capitalists in the North preferred wage labor for a reason. It was more adaptable, scalable, and less politically and socially volatile, fire and replace in case of problem, slave you own ... You can get rid of it easily like expensive machine you own.
Imagine slaves, slaves had upfront capital costs, they had to be bought, housed, fed, and guarded. In contrast, wage workers were a variable cost and more efficient for fast-changing industrial demands.
