(Following up to “Slavery and the rise of the West — US Civil War was necessary for ending slavery“.) According to Sven Beckert
Slavery did not die because it was unproductive or unprofitable, as some earlier historians have argued. Slavery was not some feudal remnant on the way to extinction. It died because of violent struggle, because enslaved workers continually challenged the people who held them in bondage—nowhere more successfully than in the 1790s in the French colony of Saint-Domingue (now Haiti, site of the first free nation of color in the New World), and because a courageous group of abolitionists struggled against some of the dominant economic interests of their time.