I have read the book too by Jared Diamond. He was right partly that geography played a role. But he neglected the role of culture. The Jews settled in the same area as the Arabs. But Israel prospered and the Arabs are mired in poverty, violence, and dictatorship. Same geography but different results. That's culture at work. Islam is to blame for creating a defective culture.
Discussion of current events
Good point Milo.
The Spanish inadvertently caused the population of the Americas to collapse due to the introduction of smallpox and other contagious diseases previously unknown in the New World. Likewise, within months of the arrival of the first British settlers here in Australia they noted an out-of-control epidemic of smallpox among the Aboriginals of the Sydney basin. That pandemic raged right across mainland Australia and decimated our native population before it had run its course.
By contrast, when the Spanish arrived in the Philippines there was no similar collapse in the indigenous population of that country: the reason was simple. The Philippines had enjoyed regular seaborne contact with mainland Asia for centuries so there could not have been a single pandemic disease that had raged across Eurasia for centuries unknown to the native Filipinos.
The Chinese for the same reason kept up their numbers after regular contact with Europeans began.
Eurasians suffered deaths from these repeat pandemics too but with each one their metabolisms developed antibodies that gave them partial protection. As a rule the very old and the very young perished but otherwise healthy young adults of childbearing age survived.