How does Jared Diamond approach the problem of why wealth, power, and technological skill began to become distributed the way they were rather than some other way?

In Guns, Germs, and Steel, Jared Diamond describes how as a researcher he has met people from all over the world. He notes that indigenous people in places like Papua New Guinea are just as smart and hard-working as people from wealthier, more technologically sophisticated nations. His book attempts to discover how, despite this lack of innate differences in capabilities, wealth and technological advances have been unequally distributed.
His answer was to look at geological and environmental factors. Some areas, such as Egypt and Mesopotamia, were lucky enough to have soils suited for agriculture and plant and animal species that could be easily domesticated. These underwent an early Neolithic transition to agriculture, leading to urbanization and the sort of food surpluses that enabled specialization of labor and technological innovation. Also, societies that were located in areas in which east-west travel was easily possible could exchange climate-appropriate innovations, leading to even faster innovation and development.