The answer to this question can be found beginning on p. 247 of Guns, Germs, and Steel. There, Diamond begins to list four factors that, in his view, help to determine whether a society accepts a given invention.
The first of these factors is, in Diamond’s words, “relative economic advantage compared with existing technology.” In other words, how much better the invention is than what the people already have. If an invention is much better than what they have, they will accept it. If, on the other hand, the invention will not help much, they will not accept it. This is why, Diamond says, the natives of Mexico did not accept the wheel when it was invented. As they had no draft animals, it was not much (if any) better than using human porters.
The second of the factors is “social value and prestige.” To me, this is a fancy way of saying that people’s tastes matter. He gives the example of Japan’s writing system. When Japan was introduced to the Roman alphabet, they rejected it for the most part and kept their difficult-to-learn system of kanji because of its prestige. In other words, the Japanese (he says) just like using kanji and therefore reject Roman letters.
The third factor is “compatibility with vested interests.” If an invention goes against things that are already dominant, it might get rejected. Diamond says that we would be able to type much faster on non-QWERTY keyboards. However, we reject these things because, among other things, those of us who have worked hard to learn to type do not want to have to learn a whole new system.
Diamond’s final factor has to do with how easy it is to see the advantages of the new invention. To me, this is closely related to the first factor. If people cannot look at an invention and see how it would help them, they will not adopt it. If the advantages are obvious, they will adopt it.
Diamond argues that these four factors determine whether a given society will accept any particular invention.