Interesting, and (so far) well-sourced. You picked a good day to post here. For some reason, Sundays is always it's-the-end-of-the-world-as-we-know-it on HN. Every week I see variations around the same theme. It's cool to have the topic covered with reduced scope (societies, not the planet at large), and in-depth.

Which brings me to my questions. One, what is "The West"? Would the French Revolution count as a civilization-wide failure? The Bronze Age collapse? Sea Peoples? The Long March? The Hellenic Era ending? Perhaps this is explained elsewhere, but some clarification would be helpful.

Two, it might be good to cover all of the "false positives" when it comes to predicting civilization collapse. It's been quite the cottage industry over the centuries. Romans were quite concerned with the lack of morals and corruption the Greeks brought them. Many believed that signaled the end of Rome. Why, some of the "new" Romans weren't even sleeping on the ground any more! They were using beds!

Three, and I apologize for so many queries, but "collapse" or "failure", or whatever you're using could also use a bit of definition. The Western Roman Empire collapsed and failed, that much is obvious. But just when that occurred is much less clear. People in Europe thought of themselves as Romans long after modern historians view Rome as being gone. I believe there are a couple of other examples of unclear failures, where the people involved in the failure couldn't see what was happening right in front of them, but none come to mind right away.

Good work. Look forward to seeing more of it!