Why did the myth of the Flood take shape in Mesopotamia and not in Egypt?

In ancient Egypt, the flooding of the Nile River was a boon. He brought fertile sludge. Flooded plots of land were valued more expensive than non-flooded ones. The start date of the spill was successfully predicted from the star Sirius.
Mesopotamia is a flat, very extensive swampy plain. When the water rose by several meters, vast areas were flooded. The floods were destructive and for the inhabitants of the region they were evil, a disaster. I think that’s why the flood myth took shape there.