Why Didn't the Aztecs and the Inca Learn From Each Other?

Si Sheppard says the Aztecs never made bronze, the Inca world did, and the two empires did not pass that knowledge to each other.

In Mesoamerica the tools of war were stone. The Aztecs could smelt silver and gold, which drew the Spaniards in, and they could not smelt iron to hold them off. The Tarascans, to the west, could smelt copper and put it on arrow points, and the first Aztec invasion of their territory was a disaster partly for that reason. Tin exists in the Americas. Mesoamerica still never turned copper and tin into bronze. The Inca did have bronze. Bronze cannot stand up to iron, and it is better than stone or obsidian. Access to it, Sheppard says, would have given the Aztecs a harder way of fighting.

Dwarkesh Patel's point is that the Europeans stacked what they learned and the native empires did not. Cortés learned from the conquest of Hispaniola, then improvised in Mexico. Pizarro knew what Cortés had done about a decade later and followed the same playbook. Sheppard says it is not clear the Inca even knew the Aztecs existed. Their societies stayed closed.