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.
The Dark Herald 
Interesting point, and maybe some more information is buried in archaeological literature or in satellite radar mapping of the jungles. Grain has to be planted, harvested, dried, moved and stored. In America, they had killed off the species that were domesticated elsewhere, so everything from planting to transport has to be done by human power. Probably a limit beyond which they can’t physically move grain, and that enclosed area bounds the maximum yield and population.
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Honestly it wasn’t moving grain that was the biggest problem.
It was growing it in the first place without an animal powered plow.
That was the real bottleneck.
Using a planting pole, seventy acres could only support one Mayan family. Mind you their farming practices were terrible. They were planting single crops year after year. Worse they were usually planting maize which rips the nitrogen right of soil. Crop failures would start after only four years.
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for not having draft animals, it doesn’t seem that it constrained New World city sizes very much:
“With an estimated population between 200,000 and 300,000, many[who?] scholars believe Tenochtitlan to have been among the largest cities in the world at that time.[14] Compared to Europe, only Paris, Venice and Constantinople might have rivaled it. It was five times the size of the London of Henry VIII.”
https://infogalactic.com/info/Tenochtitlan#History
there were plenty of extremely large cities in central and South America, as demonstrated by all the megalithic structures ( requiring large quantities of surplus manpower to construct ) they left. i’m not sure why they didn’t form large cities in North America, but “draft animals” is not a constraining factor.
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I never said they didn’t have large cities.
My assertion was that they were unsupportable without draft animals once the population reached a tipping point.
I don’t account myself an expert on Mayan agriculture. But I did study Medieval European agriculture with an emphasis on pre and post plague crop production.
I will grant that there were other contributing problems that lead to the civic collapse of Mayan cities.
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they were supporting +100k population cities WITHOUT THE WHEEL, much less without draft animals.
i doubt very much that ‘food transport’ plays much into historical municipal collapse in the absence of some other, more serious problem. like war, plague or famine. i believe some South American civs are also supposed to have collapsed due to crop failure because the farmlands were being impaired by mineralization from the artificial irrigation schemes.
ie – the existence of cities is predicated on the idea that neither the city population nor the outlying populations will do something stupid to fuck up their systemic support structures. hence, “civilized behavior”.
concerning random thoughts, BoxOfficeMojo is forecasting a +85% collapse in 2nd weekend ticket sales. that’s insane.
https://www.boxofficemojo.com/release/rl3305145857/weekend/?ref_=bo_rl_tab#tabs
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One of Charles Mann’s books, 1491 or 1493, has a chapter on the Mayans. Their main infrastucture problem was potable water. The ground water in the Yucutan is apparently salty, so they had an elaborate system of catch basins and channels to collect rain water. This needed constant maintenance. Unfortunately, the Mayans decided that war was more imortant than infrastucture maintenance, the channels silted up and they had to move.
Mann also talks about how the Mississipian civilization in N. America mismanaged itself into oblivion. The lack of domesticatable animals probably didn’t help, since it limited their ability to just brute strength their way through a problem.
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