The Mesopotamian Civilization is often regarded as the oldest civilization in recorded human history.
Oldest known...
There is zero reason to believe we have a complete picture of history. I know it's pedantic but lazy language leads to the common person having fundamental misunderstandings.
We keep finding the "oldest" stuff in that area. Because that's where we keep looking for old shit. And while looking for one old thing, we find other old things.
It's just not very easy to to search all of Africa for artifacts as it is the same 20 square miles in a desert next to the only land bridge out of Africa.
Like how people thought ancient hominds all lived in caves before we realized caves were just more likely to preserve artifacts and remains than a forest.