I'm not trying to downplay the complexity and advancement of Native American tribal life in North America. But was there any reason that massive empires and city states and the like didn't form? Was it simply an issue of terrain or lack of population or was it something else?
First, there were massive cities and empires in North America, since Mexico is part of North America. There were also pretty big cities north of the Rio Grande, like [Cahokia[(http://cahokiamounds.org/) (pretty close to modern St.Louis), which was the biggest city ever north of the Rio Grande until the last decades of the 18th century.
Also, some past threads on this sub
Why were Native American populations in South America so much larger than North?
Why are there no pyramids or temples in North America, but there are so many in South America? The question is based on a factual error, since there were mounds and temples in North America.
Why are there no ancient Native American cities in North America? Again, there were native cities in North America.