LOL what a joke, my ancestors lived on a diet of almost all bison
I highly doubt this. Meat in prehistoric societies was pretty hard to come by. When you exist on the same plane as the animals, you're subject to all the stuff they plan to do to make sure they're not going to get eaten. It's a hell of a lot easier and safer just to grow some plants or do some fishing or something.
I won't say it never happened that someone's ancestor's society was just killing it and eating bison burgers all the time but the diet where you can eat large animal meat is almost entirely a modern invention caused by our overflow of wealth and productivity.
Eating a lot of meat is not good for you, science has proven this time and time again.
Eating a lot of meat in the modern day will straight-up kill you in the long run (literally), because the meat is full of hormones, pesticides, antibiotics, disease from the conditions they were kept in, and God knows what else. Societies in the ancient world that sorted out how to eat meat consistently (one prime example being domesticating cattle successfully) started exploding across the landscape and overtaking all their neighbors, it's a pretty good formula as long as the meat is healthy for you.
Their population is sparse and they had absolutely no energy to spare to expand or rise up in the world, they were too busy with the incredible energy expenditure that is hunting. They didn't choose to do this as a success option, they just have no other option because nothing will grow in their environment, so it's hunt or starve.