Red- When you have a nice elegant theory that enables interesting research and discussion to take place, and indeed, whole eminent careers to be built on it, why rock the boat. Science and other disciplines are full of examples of this. And the Out of Africa theory is tidy and emotionally appealing, so the tendency will be to iron out the irritating contradictions and have it all nice and flat and tidy again, in time for the next dig in the Rift Valley.