> slavery was incompatible with industrialization.
From what I understand, early industrialization gave a temporary boost to slavery. The cotton gin and textile factories greatly increased demand for cotton at a time when industrialization had not yet addressed the harvesting of cotton in the fields.
The cotton gin did indeed revive slave produced cotton when it came out. But it was hardly industrialization. It was a hand cranked box. But that was not enough by mid century, and the slave economy was foundering again.
Eli Whitney's patent depicts a hand-cranked cotton gin, but I believe by the mid 19th century they were making much larger cotton gins powered by water wheels or animal power (e.g. four mules walking around a shaft.) And on the cotton consumption side of the industry, mechanized thread spinning and power looms were by then a mature technology. The industrialization of textile industry began in the 1700s, particularly in the UK where they imported huge quantities of southern cotton.
The textile industry was being industrialized - but it wasn't being operated by slaves. An educated workforce is needed to operate industrial machinery, and it was illegal to teach slaves to read.
Industrialization and slavery are incompatible.
Forced labor has never been able to compete with free labor.
I guess my point is that industrialization doesn't/didn't occur uniformly across entire industries; some aspects of industries were mechanized before others, temporarily increasing demand for manual labor in the per-industrialized segments to keep up with the machines. Textile factories create demand for field workers, steel mills and steam engines create demand for coal miners, railways create demand for workers that lay rail, etc.
Another example, in an alternate timeline perhaps, might have been the development of the western territories. Instead of Chinese immigrants building most of the rail, it probably could have been a very profitable venture for slave owners. Slave labor was used for railway construction in the south, so it's not far-fetched.
I agree that slavery was destined to lose in the end, but I don't think industrialization is a direct path to the economic obsolescence of slavery, because slave labor can compliment partial industrialization.
I seriously doubt slaves would have been profitable for the western railway. Blasting tunnels was very skilled work, and very dangerous. Would you want slaves, who hated your guts, handling nitroglycerin? You'd need as many armed guards as slaves.
Presumably the blasting itself could have been done by specialist free men. But the blasting itself is only a small part of the process. First you need to drill the holes by hand, that means beating a rock drill with a hammer for hours, just for a single hole, and you need dozens of holes for one blast, countless thousands if you're trying to go through a mountain.
There were steam powered machines for drilling rock at this time, but they were cumbersome and temperamental, most of the drilling was still done by hand. Hence the folklore of John Henry racing a power drill to see who could work faster. I believe most of the drilling in the west was done by hand, by Chinese immigrants.
Then there is the matter of the rubble. Explosives only break the rock, who hauls that broken rock? That's more manual labor.
The nitroglycerin would be of necessity readily available. Do you really want your slaves around this stuff? Think they might steal a bit and put it in the overseer's tent at night? You'd have to spend more money on armed guards and manacles than just hiring free men. Slaves were also costly to buy.
From what I understand, early industrialization gave a temporary boost to slavery. The cotton gin and textile factories greatly increased demand for cotton at a time when industrialization had not yet addressed the harvesting of cotton in the fields.