The sub Saharan kingdoms had failed to capitalize fully on the trade of the region.
Explanation:
The trade opportunist for the sub Saharan kingdoms especially in the coast had been numerous as the new kingdoms in South east Asia as well as India and China had opened up well to trade in the time which would have been profitable for both.
This never happened on a larger scale and the business that did happen was not permeated through development into the mainland and only the coasts became rich.
