> I don't think the Mayans ran out of anything. Neither do I believe the Romans ran out of anything.

Is this true? I thought it was drought and deforestation and over-farming that sped up the Mayan decline and that soil erosion and exhaustion and agricultural decline aided in the fall of Rome.

https://science.nasa.gov/science-news/science-at-nasa/2009/0...

One suggestion I heard was that the Mayans were a bunch of imperialist tax collectors and their "empire" simply started refusing to pay tax when the military advantages were no longer so important.

You could probably say the same about Rome. Once everyone in the empire could out-Legionary the Romans (the provinces were the main source of military might anyway at this point), sending tribute suddenly became a bit of a waste of time. Any disruption can trigger a chain of revolts. A revolt could be armed, or a soft revolt where the locals start acting like feudal lords and claim it's necessary to keep the peace.

Rome got much (most?) of their grain from Egypt (which renews fertility due to annual flooding) and the cause of the Mayan collapse is unknown but I highly doubt it was primarily scarcity driven.

Societies collapse from social factors, not just resource scarcity and social factors are in my opinion a more common cause. War, internal conflict, and political instability.

And my favorite theory, the rise of parasitic and short sighted bureaucracies which snuff out the creative and competitive impulse of a culture.

That link appears to disagree with you regarding the Mayans and even points out that ecological issues can fuel and exacerbate social, political, and cultural problems. Of course these things are multifaceted but it seems obvious that a multidimensional domino effect can occur when kick started by ecological issues. Look at what happened with COVID. Gun and ammunition purchases were off the charts, increases of homicidal crime, civil unrest, unemployment, etc. Such a "simple" thing as a virus destabilized society in multiple ways. Just imagine if it was food and resource scarcity.

> Societies have collapsed for reasons other than resource scarcity. In fact I'd say more often they collapse for reasons other than resource scarcity.

This is a bit moot, considering that resource scarcity is a very, very good reason for societal collapse, as well as potential a root cause of other reasons you cite for societal collapse, and resource scarcity is exactly what we are beginning to experience.

Check out Joseph Tainter's Collapse of Complex Societies. He looks at a large number of historical complex societies that collapsed and suggests that they collapsed when the cost of the complexity exceeded its utility. A very appealing concept. His arguments about why our society is not at risk were not convincing.