With respect to at least Egypt bear in mind that the areas frequently photographed are the dramatic desert parts

Definitely not only Egypt. The Fertile Crescent from the Levante along the north end of the Syrian Desert all the way through Mesopotamia to the shores of the Persian Gulf was generally very, well, fertile land (as the name suggests).

Unfortunately, Euphrates and Tigris nowadays contain much less water due to climate change and dams built in Turkey, and farming cannot be done reliable in the lower regions anymore.