New paper quantifies how quickly Southern planters recovered from the civil war
In most cases they still owned large plantations which was always the real source of wealth. Slaves were the means to extract that value from the land. The end of the war lined up with serval advancements in farming technology (or at-least the widespread use of them). Combined that with many of the former slaves having no transferable skills and very limited bargaining power forced them to work on the plantations for horrible wages.