Here are some past threads that might answer your question:
Why weren't civilizations in the ancient north America's more advanced? by /u/RioAbajo
Why were Native American civilizations so far behind their counterparts throughout the world? by /u/The_Alaskan
What differences caused the Mesoamerican societies to be much more successful than Eastern North American societies? by /u/Reedstilt
To clarify, are you asking about all American Indians (Including the ones in Mesoamerica and the Andes?) or North American Indians north of the Rio Grande?
Thank you 😀