If there was a contact with the old world and these people came all the way to the New Mexico area, wouldn't it make sense that the indigenous peoples would have picked up a little of the technology from these strangers, like the wheel?
You would think so huh. But then again, they didn't have any roads, did they? A better question might be, "Why didn't they all 'catch' the diseases from the old world and die then, instead of waiting for the Europeans of the 1400-1500's?" (I do believe there was travel between the new/old world in ancient times. I've always wondered about this 'disease thing' though.)