At some point rising insecurity becomes expensive. The elites have to pacify unhappy citizens with handouts and freebies—and when these run out, they have to police dissent and oppress people. Eventually the state exhausts all short-term solutions, and what was heretofore a coherent civilization disintegrates.
I don’t know how an entire civilization can become “incoherent,” though I’m sure there are examples of the above rule.
That said, I’ve often taken heart from Japan’s, Germany’s, and China’s survival, rapid recovery and rise from the ashes of war and revolution in the 20th century. Maybe they did “disintegrate” temporarily, but somehow they got back on their feet. Ancient traditions in each country have reasserted themselves. There are beers and I think breweries in Germany that go back 5 centuries. Their language is unchanged. The elderly are still held in high esteem nd cared for by their children in China. (This may be changing.) I don’t know what’s left of Japan’s pre-ww2 civilization, but it seems that things have a way of working themselves out over time absent.
What civilizations have recently disappeared?
As to the power of elites, an argument I used to have with genuine hard core commies involved “rising inequality.” I don’t think inequality is very important, to be honest — is the increasing value of the stocks owned by elitists Warren Buffett, Bill Gates and Elon Musk really hurting anyone? How? Inequality is used interchangeably by some with poverty, which I do think is important but am a loss to know how to eliminate. Families that stick together and support each other, no matter what, and a higher regard for self reliance and discipline (speaking of the Japanese) of each family member, would go a long way.
But “family” is a quaint idea, and growing more quaint as popular culture scoffs and government grows, but what’s the alternative? A Great Society envisioned by strangers in Washington?