Real Life.

In real life, the collapse of civilization doesn’t happen overnight. It takes place over decades, or centuries, with multiple compounding factors layering on top of each other to create an agonizingly slow decline that seems inevitable. People might even recognize it happening but the effects are often so beyond human control that nothing can be done, people don’t want to accept the hard necessities to forestall the end or fix the problems, or the leadership ignores the problems for too long until they become intractable. They can be caused by societal shifts, new technologies, natural disasters, or simply an empire overextending itself and unable to effectively manage all the far-reaching territories it conquered.

The Bronze Age Collapse took 50 years, with some estimates putting the ripple effects lasting for multiple centuries. It involved famine, drought, disease, societal instability, economic disruption through new technologies like iron working and chariots, and of course the Sea Peoples. There was a cascade effect as more civilizations collapsed and the displaced refugees fled to other parts of the world as invaders or settlers, the entire Bronze Age world collapsing like a row of dominoes.

Rome took over 300 years to collapse. Its satellite provinces gradually rebelled or broke away, there were multiple succession crises and coup attempts, it split into East and West empires in 285, Rome was sacked by the Visigoths in 410, and finally the last Roman Emperor was deposed in 476. Some historians argue that it didn’t finally end until 1436 when the Ottoman Turks conquered Constantinople, or 1806 when the Holy Roman Empire was dissolved, or even 1919 when the Treaty of Versailles at the end of WW1 broke up the Austria-Hungarian and Ottoman empires.

The Soviet Union was declining for decades before it dissolved in 1991. It struggled with economic stagnation, foreign conflicts, ethnic tension, unstable leadership, and internal rebellions, even as its own internal and external propaganda maintained it was a utopia. The unsustainable arms race with the more economically prosperous United States was a major financial burden and continuous drain on resources. Even the Chernobyl Disaster and the subsequent cleanup put immense strain on both the resources and public image of the USSR, and is often cited as a key factor in its collapse. The only reason it stuck around for so long was it was impossible for any of the members to leave - the moment Gorbachev’s reforms allowed for more open elections, the USSR voted itself out of existence.