That and the Natives were still technologically in the Neolithic age. The didn’t work metal, weapons and tools were still knapped from stone. Other than dogs, no domesticated animals that I know of. There was no way that they were going to fend off the influx of Europeans.
Uhhhh. Yep, they did. They didn't work Iron, but they sure did work metal.
How prehistoric Native Americans of Cahokia made copper artifacts
Metallurgy in pre-Columbian America
etc.