I mean, yeah...
It's like how early hominids were labeled "cavemen" because we kept finding evidence of them in caves. They didn't just live in caves, or even really had permanent shelters in caves. It's just where evidence was most likely to be preserved.
Similarly the cradle of civilization being one of the most likely places for remains to fossilize would be insanely unlikely.
It's still somewhere in Africa, just not that exact spot.