Worth noting:<p>- Historically, human civilizations needed nothing resembling a "wiped out" disaster to completely collapse. Put a bit of stress on 'em (modest & local climate change, "mining out" some so-convenient resource, or whatever), or just give 'em a few generations of "the good life" to get complacent, and things often collapsed. Usually, the "why?" amounted to "it's easy to be short-sighted and stupid, and that's pretty much how they behaved".<p>- A human civilization built on pre-1800-ish technology can suffer fairly complete collapse, and the survivors rebuild pretty quickly - repeatedly if needed. The vast majority of the population are <i>relatively</i> self-sufficient farmers. Livestock breeds. They grow their own seeds. There is little long-distance transportation, and that's mostly via wooden boats / barges / ships. And all the skills and knowledge needed to maintain (or rebuild) a "95%" version of a fallen civilization can fit into a few dozen human heads.<p>- Today's human civilization would fare vastly worse in any sort of "complete collapse" scenario. Supply chains, even for critical parts of our infrastructure, are global. And you'd need <i>tens of thousands</i> of experts to have all the skills required to rebuild a "95%" version of today's world.