I do think that Diamond’s argument on this point, found in Chapter 8, makes a great deal of sense. To understand why this is so, let us understand Diamond’s argument. To Diamond, there are two related reasons why the Native Americans did not domesticate apples.
First, the Native Americans did not domesticate apples because apples are very hard to domesticate. Diamond tells us, on p. 156 of the paperback edition of the book (last page of Chapter 8), that it took people in Eurasia 8,000 years from the time they started domesticating plants to be able to domesticate apples. Since farming did not start in the eastern US until about 5500 AD, Native Americans did not have the same amount of time in which to domesticate apples that people in Eurasia did.
But why didn’t farming start earlier in the eastern US? Diamond says that this is because there weren’t as many good crops to be domesticated in that region as there were in Eurasia. As he says on p. 150, there were only four seed crops and one container crop and those “fall far short of a complete food production package.” Better crops did not arrive from Mexico (problems caused by having a north-south axis) until about 900 AD. This meant that farming wasn’t really a viable way of life in eastern North America simply because of a lack of good native crops.
This is, to me, a very convincing argument for why it is not the Native Americans’ fault that they failed to domesticate apples.