I recently saw an article that asserted that all cities eventually become insolvent.
The reasons for this is that there is a cycle that begins with a period of rapid growth due to highly successful trade, industry or other. Infrastructure is built up to meet the demands of a rapidly growing population. Then the population outgrows the income provided by the the highly successful trade, industry or other. The infrastructure can no longer pay for itself and the city becomes insolvent.
I wonder if that’s why the Mayan cities collapsed? Although the primary infrastructure they desperately needed was grain agriculture. In Eurasia that was the solution early cities had to rapid population growth. An all bread diet isn’t all that tasty or healthy but it will keep you alive.
The Mayans couldn’t use that solution because they were missing a vital element of successful grain agriculture. Domesticated draft animals. In Eurasia, there were horses, donkeys and oxen. But in America there no good candidates for domestication. The only animal that was even close to usable was the lama and they lived in the mountains.
Without grain agriculture when the population hit the tipping point, everyone found it easier to walk back into jungle.