“Why did Slavery fail in America?”
Mostly because industrialization and mechanization, with concurrent large-scale immigration of relatively intelligent, educated, motivated European workers, made slavery uneconomical. Studies such as William Freehlings’ “Road to Disunion” demonstrate that the presense and “density” of slavery thinned steadily decade by decade and north-to-south before the Civil War. Pro-Slavery politicians sensed the closing window; Kentucky and Maryland already lacked enough slavery interests to pull them into the Confederacy. Virginia’s slavery interests were declining and without Virginia, no Confederacy. McCormick’s horsedrawn sowers, reapers, etc., that came out soon after the CW would have finished slavery off. It’s interesting how 5 to 10 years of technological evolution would have made the CW unnecessary.
Industrialization is THE correct answer.
Had the war not been fought, slavery would have ended n its own by the 1880’s.