still watching Germs, Guns, and Steel

In the 1960's New Guinea was still using stone tools. Why have the never made metal tools and a surplus of food. The middle East was very fertile which gave it the name " The Fertile Crescent". the fertile crescent collapsed and lost its head start due to high climates that were not suitable for growing very prosperous crops. The people then moves to the west and east for a search of food and better living. They were moving along the same latitude lines which they did not know that, in many cases countries along the same latitude share the same animals and climate. The climate was the reason they moved in the first place. the animals like pigs and goats, and crops like wheat and barely moved into India and china and down into Egypt and into parts of Africa. they soon have a surplus of food fit for a king. It moved into Europe which feed inventors and great historic people. then everything food into America "The New World". There wasn't a single cow in America until the spread of animals and crops from the fertile crescent. now America has millions of cows. So the overall answer Jared Diamond was looking for was, New guinea just never ended up with the technology to advance like everyone else.