I'm currently trying to write a TL which has, as one of its premises, a phasing out of chattel slavery in colonial America in favor of indentured servitude. I'm trying to figure out what the butterflies in Africa might be.
I know that many African nations of this era (such as Dahomey, Oyo, and Ashanti, among others) boosted their economy by selling slaves to Europeans. What happens if that income is reduced or cut off?
Could the West African kingdoms recover from the loss? Were there any states that didn't participate significantly in the slave trade that might be able to benefit from their weakness? Or would it just be a minor inconvenience that they could easily ignore?