> It seems that once $NICHE-stream demonstrates sufficient demand, Netflix can simply license the same content and provide customers with a superset of the content that $NICHE-stream provides.

I would not be so quick to discount the difficulty of building a large number of commercial relationships in the long tail of African production. The mere time investment and tedium of dealing with producers who are not used to distribution channels beyond their local habits is a barrier to entry - and hence a valid strategic positioning.