I am strongly positive on "Guns, Germs, & Steel"; David Kedrosky is even more positive; so let me, against þe grain, try to set out what can be said in critique of Diamond þt is not stupid...
It's striking how many of the people that criticize Jared Diamond are big fans of David Graeber, which makes you wonder if the debate is really about historical accuracy at all.
Guns, Germs, and Steel was my favorite "big picture" generalist overview of the development of human society before Slouching. As for the oversight which you identify in the final pages of Guns, perhaps he felt constrained by publishing with trade publisher. You have certainly expressed frustration (?) about the page limits you faced.
Guns, Germs & Steel struck me as an old fashioned geography book, perhaps one from the 1920s or 1950s. These were treatises on geographical reasoning, so they dealt with things like transportation costs and resource availability. The more adventurous of those books would discuss out how geography could shape commerce and society but stayed away from ideas about racial characteristics. A modern critique of these books seems to be that they ignore such racial characteristics as the intrinsic war-like, exploitative nature of Western Europeans. Go figure.
One of the things Diamond did with Guns, Germs & Steel was to get people thinking about geography at a higher level. That's what physicists and chemists do with conservation laws. The energy or atoms have to come from somewhere and go somewhere. You can analyze a black box based on its inputs and outputs, and any imbalance has to be accounted for by a change in state. It can be deeply unsatisfying if you want to understand the details of the mechanism, but you can get useful answers. If you push this in on the top, then that comes out on the side. You can predict the force and velocity, but have no idea of how the black box changes the direction. As I said, this can be deeply unsatisfying, but it is incredibly important and useful. Noether wasn't wasting her time with her theorem.
The Dover Circle empire has its historical precedents, expanding empires driven by technological and institutional change. The Mongol Empire was built on horse based warfare and effective foraging. As with our more modern empire, it had limits, but it conquered a good chunk of Asia. You can look back at the Iron Age empires in the Mediterranean with Alexander as the precursor followed by a more logistically and socially sophisticated Rome. The Incan empire was built on its organizational skills and its control of the highlands. I'm sure someone could find similar patterns in the unification of China. There's more to those stories of standardizing the writing system than imperial whim.
I though Guns, Germs & Steel did a good job of what it set out to do. No, it doesn't even try to explain how the black box turns a downward force into a sideways one, but that was never its point.
Diamond’s ideas weee fantastic in Guns, Germs, and Steele. A rare time when an outsider doesn’t just sell books, but provokes serious thought that carries over for at least one generation.
That said, his other works aren’t equal to it. Collapse is my favorite read, but it views history very narrowly for through it’s own thesis (human-caused ecological damage), and only counts the hits and none (e.g. the majority of collapse events) misses. It’s a steep slope down from there.
Here is your next book- 1500-1900- colonies, coal, cognition leading to corporate labs, unions, and monopolies
banking too Dover circle= Venice-London