I've watched all of CGP Grey's videos but his latest struck a funny note. Is it accurate?

He mentions near the beginning that there was a huge population of native Americans before Columbus but then later on says that they weren't living in large cities, but I distinctly remember seeing here and on /r/badhistory that Native Americans did have rather large cities. Further on he seems to imply that llamas aren't all that good as domesticated animals which strikes me as a little eurocentric.

What validity is there to this video? What is he simplifying or glossing over or just simply mistaken on?

link: https://www.youtube.com/watch?v=JEYh5WACqEk