The Pilgrims landed in Massachusetts in 1620. In Jamestown, Virginia that year, the first cargo of African slaves was brought to America. The reason was Typhoid. Typhoid is a pathogen that most Europeans and Anglo-Saxons carried no immunity which the exception of the Welsh. There were not enough Welsh for the work to be done. One hundred years of trying to get the Jamestown colony going had failed. English people arrived in Virginia only to become ill working in the humid, fetid marshes of the New Land. Typhoid is a lingering disease that if untreated flares up just as warm weather arrives. So a workforce of Typhoid-immune workers was needed.
Now paying wages in the risky and labor intensive venture of agriculture never had and did not work. It was exhausting and the heat of the day only permitted a few hours of work in the sun. It was a given, housing, food and water in exchange for work. It was lousy work so permitting resignations was out of the question. These facts were even prevalent in Southern New Jersey where many people had no love for Abraham Lincoln and his ilk before, during and after the War.
Up North, people quickly found that the shorter growing season made other pursuits more profitable. Why bust your hump lifting rocks out of the Earth when the Natives were happy to trade?
Now after the adoption of the Constitution and the "slave compromises", Virgina "volunteered to permit the ending of the importation of slaves". This granted the likes of GW, TJ and others a monopoly on slaves. This was before the advent of inorganic fertilizers so crop failure was a real risk back then and it was happening because what tobacco did to the soil. In Virginia, if your crop failed you could sell your slaves to someone starting a plantation further south and pay your mortgage! Black slaves became the gold of the 19th century in America. Combine that with the advent of textile machinery in the UK and the North and there you have it!
Thomas Jefferson switched his farming to wheat and recent diggings on his lands revealed a highly benign employer-employee type relationship with his "slaves". But he did sell some. So did the Jesuits at Georgetown. This was the worst of African-American experience the breaking of families!
Robert E. Lee who was raised in Virginia's landed gentry ran from agriculture as a career. But as luck would have it he ended up as the executor of his father-in-law's estate. He found the only thing of value were the slaves and made his choice when Abraham Lincoln sought his service for the North. He had in-laws that needed money!
America would not have been possible without African-Americans. Without them we would have never established the economic independence that eluded Canada until the 20th century. Our greatest crimes against them was the breaking of their families for economic gain and the assumption of superiority to justify their labor while white settlers sat and threw up due to Typhoid.