Part of the thesis is that a certain level of biological homogeneity increases the speed in which the complexity of economics, language, and political structure develop which is part of why I think America, Russia, and China grew to be the powerhouses they are today. (Side note; I think the civilization of the U.S is the one most heavily affected by introduced species and for the most part, in a good way. Though it obviously has its limits because well, look at eskimos and shit- some environments are just too extreme for civilization to prosper. And obviously any indigenous "tribal" culture today is either going to be permanently stunted or commodified in some way. They kind of just lost their chance. ** Now even ignoring the Aztecs, who could have very easily developed into a contemporary civilization if they weren't defeated you could see the Native American tribes developing all the anthropological hallmarks (of course, much faster and more common post-colonial efforts), traditional "wars" were declared, there were trading patterns, they had knowledge unexpected of "savages" (bro they knew astrology they knew how to read the stars) that impresses midwits, some tribes settled in an area, some used agriculture, and they were forming larger coalitions. But again, contact with the more civilized permanently stunted and warped them. Basically, I think this romantic view that "the Natives knew what was up" and that it was just human greed that caused, specifically Europe, to develop the way it did is bullshit. I think all civilization develops uniformly, the Natives weren't wise beyond their years, they just had conditions that allowed them to maintain that way of life. And it wouldn't have lasted forever. It probably wouldn't have lasted even a 100 years more without European contact, again, even barring the Aztecs. Every radical cry to return to pastoralism or agrarianism reeks of ignorance or woo-woo New Age delusions.