The "Fall of" wherever is almost always a political discontinuity - and not infrequently one only apparent in retrospect. It's also generally a long drawn-out process. One of the rare exceptions was the fall of the Neo-Assyrian empire, which was conquered and its capitals captured, sacked and depopulated virtually overnight. That, interestingly, put the skids under one of the conquering powers. However, the Fall of Babylon, when it came two generations later, was very much a matter of the Persian King of Kings marching in, deposing the current ruler and putting himself on the throne.
As for Rome... hmmmm... If you ask a Roman, you'll get a blank look: the city is quite clearly still there. In fact, if you look, you'll see SPQR stamped on every piece of municipal metal work [although I suspect that that was Mussolini's idea]. The city was a going concern right through late Antiquity and throughout the Middle Ages. It had also ceased to be the political centre of the Empire long before the putative Fall: the capital had moved to Milan by the middle of the 3rd century, wandered through various European and Asian cities [at one point, under the tetrarchy, there were 4 capitals, none of them Rome] and when the last Western Emperor was deposed in 476 was at Ravenna.
It had also, by 476, been at Constantinople for a century and a half. If you had asked any Byzantine of the 6th, or even the 12th, century about the Fall of the Roman Empire, you'd have gotten that same blank look, followed by 'nonsense! this is the New Rome!' I'm not sure that they ever completely stopped calling themselves Romans, but if they did, it didn't happen until nearly the end - sometime in the late 13th or 14th century at the earliest.
It's true that the population, as well as the political significance, of the city of Rome had declined a long way from its peak by 500, but that was the result, not the cause, of the political and economic failure of the western Empire, and it started with the beginning of the Crisis of the Third Century around 230; it was that disruption that led to a decline in the supplies available to the city. However, in the East, where that disruption never happened, by the 500s Constantinople had far surpassed Rome at its peak.
The only place where issues of resources may have been a major factor in the collapse of a civilisation was in the Classic and Post-Classic cities of the Yucatan. Nobody knows why they were abandoned, but agricultural collapse is a leading contender.
DDHv wrote:< snip >
Does anyone know if the supply problem was a contributing factor with Rome or any other urbanized real life historical polities which have fallen
