There's always room for discussion, but perhaps these topics will answer your inquiry.
Why did the Natives that lived in North America not attain the same depth of organization, architecture, and city building as those in Mesoamerica?
Why didn't native Americans in North America build great stone cities like the Aztecs or Mayas in South America?
How large/common were cities in North America before Europeans' arrival. What was the largest city north of Mexico?
Why are there no ancient Native American cities in North America?
Why aren't there any ancient ruins in North America?
And for clarification, Mexico, its history, cultures, and pre-Columbian urban centers are a part of North America.