Well they failed by becoming subjugated by the European settlers, dying from diseases by the millions. That's what the book is about. I don't see a way to paint that in lovely colors? What about that isn't "failure"?

The argument here was that Diamond's theory is wrong because the native Americans could have domesticated the bisons after all. The claim that they are too difficult to tame is dismissed as "crap". Then it seems to me why they were not being domesticated needs another explanation (if the one from Diamond is not good enough). Just random chance?