The whole supply chain collapsed ... because of tariffs.
Meanwhile, North of the border, at the banking center of the southwest (around 1,000 AD), in Chaco Canyon, NM, chips of turquoise were the preferred currency. Turquoise is typically found on top of copper deposits.
https://en.wikipedia.org/wiki/Chaco_Culture_National_Historical_Park
Many, many moons ago, I had a double major in college. My first love (study wise) Spanish, and archeology. While I learned that studying archeology is, yes, fascinating, you cannot pay a mortgage, or any other bill. Before dropping the archeology major, I was able to participate in some Kalifornia, and then Central American archeology digs.
Of all the books I wanted, or was forced to read, two stand out, and I recommend them wholeheartedly.
The Hummingbird and the Hawk - by R. C. Padden.
It documents much of the Mexico, and especially the Aztecs before and during Cortez. When Cortez arrived, Moctezuma II ruled. There was a General behind the scenes named Tlacaellel. Tlacaellel had the ear of Moctezuma I and II. It is a very well written book, using original, ancient sources.
My other favorite is The Discovery & Conquest Of Mexico by Bernal Diaz Del Castillo. He was a soldier under Cortez, and survived it all. In his old age, he was blind and poor. He was sad that he had not much to pass on to his children and grandchildren. He decided to document his account of what he did and witnessed. Being blind, he dictated the entire book.
I think we can conclude that they were preparing for an attack by the White Walkers.
A Coast-to-Coast Trade Network, not to be confused with a Coast-to-Coast A.M. Trade Network where the gray aliens used bigfoots to mine for obsidian and traded it for chupacabras.