> Under this scenario, elites push society toward instability and eventual collapse by hoarding huge quantities of wealth and resources, and leaving little or none for commoners who vastly outnumber them yet support them with labour. Eventually, the working population crashes because the portion of wealth allocated to them is not enough, followed by collapse of the elites due to the absence of labour.

Can anyone give a single example of a society that has collapsed in such a way? The scenario has certainly occured many times - 1790s France, 1910s Russia, etc - but every time to my knowledge ends with the commoners rising up against the elites who simultaneously rely upon and stifle them. Even if the elites do put down an uprising, there's a new uprising a few years later. There's typically change after these revolutions, but it's still fundamentally the same society.

> Take, for example, the rise and fall of the Roman Empire. By the end of the 100BC the Romans had spread across the Mediterranean, to the places most easily accessed by sea. They should have stopped there, but things were going well and they felt empowered to expand to new frontiers by land. While transportation by sea was economical, however, transportation across land was slow and expensive. All the while, they were overextending themselves and running up costs. The Empire managed to remain stable in the ensuing centuries, but repercussions for spreading themselves too thin caught up with them in the 3rd Century, which was plagued by civil war and invasions. The Empire tried to maintain its core lands, even as the army ate up its budget and inflation climbed ever higher as the government debased its silver currency to try to cover its mounting expenses.

The Roman empire did not expand significantly beyond the Mediterranean, with only very limited expansion after Augustus. Where it did expand, such expansion was mostly to make defense of the empire easier by removing salients, reaching natural barriers, shortening communications routes, or eliminating areas frequently providing material aid to rebellions. The inflation and expensive army upkeep was caused by the civil wars as each successive claimant would print more money to pay their supporters. At the end Rome did massively expand its bureaucracy, but this was in an effort to restore centralized authority after a century of infighting. During late antiquity there was technological stagnation and no understanding of what we would consider basic macroeconomics, both of which caused the fiscal weakness of which the bloat was just a symptom.

> On the other hand, Western societies may not meet with a violent, dramatic end. In some cases, civilisations simply fade out of existence – becoming the stuff of history not with a bang but a whimper. The British Empire has been on this path since 1918, Randers says, and other Western nations might go this route as well.

Europe fought two catastrophic wars within a generation. Nevertheless, the British empire has not faded, merely transformed slightly. Throughout the 20th century Britain transferred most of its power peacefully to the US in exchange for becoming a core part of America's hegemony. If Washington is the Rome of the current world order, London is the Constantinople. Britain may not be able to draw upon exactly the same resources by exactly the same methods as at its zenith, but the fact is most of the world is currently in the economic and cultural thralldom of anglo-powers strongly aligned with Britain. Similarly the major European powers continue to wield enormous influence. France and Germany have essentially created a land-empire controlling most of the continent. Of the great powers 250 years ago, only Spain (whose empire was absorbed by military might into the American sphere of influence), the Ottomans and Austria (both of which collapsed rapidly again under military strength of the Anglo-French alliance) have really lost significant influence.

I am extremely skeptical of the predictions of models that seem to be based on fundamental misunderstandings of history.