American Renaissance had a video discussing antebellum researchers determining that a black man was only good for working 1/3rd of the hours of a free White man, and that it was impossible for any amount of violence or cajoling to get a black to be even half as productive as a hired White. Elsewhere it was mentioned that slaveowners also had to buy very expensive special "negro-proof" tools for the slaves as slaves would purposefully break tools just for the lulz. Humorously, this video even points out that Abolitionists got Northern backing by claiming that if blacks were freed that they would then become ultra-productive, dirt-cheap laborers (whose presence would, of course, destroy Northern cities). Abolitionists might have been the greatest trolls of the 19th century. For source, here's a link to the main AmRen video referenced: https://www.amren.com/videos/2019/09/did-slavery-make-america-rich/