Why did the Spaniards ultimately prevail in New Mexico?

One of the many reasons was that the Aztecs had enslaved many other tribes of Indians across the land and these tribes rose up and helped the Spanish defeat the Aztecs. Since the Aztecs were the only ones with a well organized LARGE society, and the newly freed slaves couldn't compete militarily with the Spaniards, it was easy for Spain to take control. It also didn't hurt that the scientifically advanced Spanish invaders had items that would appear even MORE advanced to a more primitive people.