In the book "Guns, Germs, and Steel", how did Diamond reword the major question which inspired his book?

In Guns, Germs, and Steel, Diamond says he wrote the book in response to a question from a New Guinean named Yali.  Yali's question was this: 

"Why is it that you white people developed so much cargo and brought it to New Guinea, but we black people had little cargo of our own"(Diamond, 14). 

After thinking about the question for a while, Diamond saw that the true question was much more broad and universal than Yali's initial question. He reworded the question as follows: 

 "Why did wealth and power become distributed as they now are rather than in some other way?" or "...why weren't Native Americans, Africans, and Aboriginal Australians the ones who decimated, subjugated, or exterminated Europeans and Asians" (Diamond, 15).

This question is what Diamond's book attempts to answer.