Did Eurasia's dominant East-West axis 'turn the fortunes of history'?

Guns, Germs, and Steel (1997) is Jared Diamond's Pulitzer Prize-winning effort to explain the contrasting histories of Native Americans, Africans, and aboriginal Australians vs. Europeans and Asians. One of his intriguing proposals was that Eurasian political and military dominance could be partially explained by its unique continental orientation.