The US was a slave economy in the south and the south did not industrialize until after slavery was abolished. That was a big part of why the south's political power relative to the north was weakening before the Civil War, was a big part of why the south eventually lost the war (they had the more competent generals and their army fought better but the north just had far more people and far more ability to keep its army supplied) and was also a big part of why the north was the stronger region economically long after the war.
If the south hadn't gotten paranoid that Lincoln was going to take their slaves away (he wasn't), they might still have slavery because the slave system meant that the southern elite didn't have to do any work whatsoever (which is basically the gist of why Calhoun called slavery a "positive good"). Sure, they weren't ever going to be as rich as the northern tycoons but they lived far more comfortable lives and didn't see any reason to change that. The north had given up slavery because, in the late 1700s before the cotton gin, it seemed like it wasn't going to be economically viable in the future and most of the founding generation viewed it as a "necessary evil" and genuinely wanted to get rid of it as soon as they could but felt they couldn't (Jefferson, a slaveowner who owned slaves he wanted to free but couldn't because he was always deep in debt, is probably the most famous example of this point of view). Northerners also believed in the ideal of the self-sufficient family farmer and (especially in New England) a Calvinist work ethic. When you regard leisure as a sin, you don't have as much interest in being freed from having to work.
In short, I think the slave economy is a sufficient explanation for why Rome didn't industrialize. When you have tons of slaves and the republic/empire was always fighting more wars to get more slaves, why would you need machines? Especially when the machines would likely require free men to do work to maintain them.
>they had the more competent generals and their army fought better
That's a pretty strong claim. Can you share your source?
My impression has always been that Southern leadership (including generals) spent most of the war LARPing, without any real understanding of how badly things could go for them personally, with their forces having no particular tactical advantages advantage over the North.
Much of my understanding of pro-slavery thought comes from Calhoun: American Heretic by Robert Elder. Calhoun was dead by the time of the war but he was the south's most important intellectual and he was at the center of American politics from the War of 1812 that he helped start until he died in 1850 after paving the way for the Civil War.
2 speeches that are really good in terms of understanding the motivations of both sides at the beginning of the Civil War are the Cornerstone Speech by the Confederate VP (Alexander H Stephens) and Lincoln's first inaugural. Neither speech is particularly hard to read especially with Wikipedia available to look up unfamiliar terminology (i.e. "internal improvements" = 19th century name for infrastructure spending and "domestic institutions" = polite euphemism for slavery). Its especially fortunate for the sake of history that Stephens came right out and said what the Confederates believed because it makes it easy to refute the "it was about economics not slavery" line of argument from Confederate apologists. Lincoln's first inaugural is important as well because it refutes the "it was always only about slavery" argument you sometimes hear in response.
One rather interesting angle in the Cornerstone Speech is how Stephens cites Adam Smith's economics. In the north, the economic nationalist "American School" of Friedrich List and Henry Carey (Carey was Lincoln's primary economic advisor) was more influential than Adam Smith. Unless you're really interested in reading economic theory, I'd say the Wikipedia article on the American School of economics is sufficient to get the gist of the economic ideas that influenced Lincoln.
I'm not entirely sure what to recommend regarding the abolitionist movement because that's an area that's already heavily emphasized in the American education system, at least in my experience. I'm also not sure what to recommend regarding the wave of immigration that finally shifted control of the federal government from south to north in 1860 but this would definitely show up in the Census data and you can still see evidence of it today in how white people from the south are more likely to have English last names than white people from other parts of the country (the mid 1800s wave of immigration was heavily Irish and German).
Another great source for learning about what happened is to get a chance to talk to tour guides at the Civil War battlefields. I think most of my history professors from when I was majoring in history also did tours of the Gettysburg battlefield. The best time to visit is when it isn't as crowded. In the case of Gettysburg, that means avoiding the first 2 weeks of July (reenactment week followed by biker week) unless you specifically want to see the reenactment because the traffic is notoriously awful for those 2 weeks and everything is going to be packed.
US industrialized first (and most) in the parts without slaves.
That slavery is bad for industrial production was a major abolitionist argument. It's been repeated for at least 150-200 years.
de Tocqueville dedicates many pages to just that aspect. He describes sailing down the Ohio, seeing on the right bank teeming with factories and mills, and on the left one only loafers and undeveloped land.
In pop culture too; in Gone with the Wind, Rhett Butler is the cosmopolitan embarrassing the old southern aristocrats at cocktails parties, regaling stories about the Union being flush with money and factories, the south being a backwater. That's how he knew which way the war would go.
Only about half of the United States was a slave economy. In the north where slavery was not prevalent, industrialization outpaced the agrarian south. Then after the US Civil War, industrialization took off with the First Transcontinental Railroad being completed in 1869.
The real reason is that wage slavery in the North is more effective than chattel slavery in the South.
When the slaves imagine themselves free and have a slightly greater amount of agency, they are more productive than those who are motivated by the whip alone.
Mostly the North industrialized, whole the South relied on slave labor as long as they could and then sharecroppers and other forms of barely-not-slavery.
The "funny" part about those barely-not-slavery practices, some were outlawed and successfully defended in court by arguing it was... actually slavery, which was illegal but had no "or else".
The US didn't crack down on this until World War 2, and that was just because they were getting bad press about it.
At the time slavery existed, north was much more industrialized then south. The free labor ideology made North have a lot more small producers trying to innovate and earn money in market.
South ressembled and seen itself more like aristocratic gentlemens so to speak. Slavery meant that trades and smaller production were jobs for slaved, looked down at.
And yet the majority of the free, antebellum South was poor. DuBois got it right about the poor Southern white being himself bamboozled by racism as well.
There was very little direct cross though. The industrialized places (cotton milling etc) almost never had enslaved workers. Those were mostly on the plantations.
What is more US slave economy was worse. In Roman times you can become free. It was common for slaves to be paid wages, treated well, and given their freedom.
(Not OP, idk how she defines it). Freedom is a spectrum. There are some parts of American work life which limits people's freedom. The non-livable wages for much low income manual labour means many needs to work multiple jobs, and makes it hard to save money, so you live hand to mouth (less freedom). Tying healthcare for you and your family directly to your current job is a major freedom-remover, even if you save up money to survive a month between jobs it can literally bankrupt you if you or you family gets sick then. There are of course places which are worse, but there are also places in the world where people can quit their shitty jobs knowing that their kids will still get healthcare and school no matter what.
