My theory makes it plain that civilisations behave like any other creature in that they rise to a prime then fall into increasing confusion and impotence until dissolution.
I doubt that an Armageddon will terminate humanity as such calamities usually exist only in the fears of cowardly citizens. Undoubtedly the existence of weapons designed to kill by the million makes it probable that some of them will be used, but I do not believe that this will result in the extermination of our species. Nor do I believe that the popular fear of some kind of toxic pollution poses a significant danger except in the mass hysteria such a fear may generate.
I suspect the future will see huge reductions in the numbers of people as our ability to solve problems diminishes and chaos overwhelms humanity, but I doubt that the new dark ages will be much different to the old dark ages.
If humanity disappears, I imagine it will be because it evolves into something that is no longer all animal, but a hybrid of machine and flesh; or just machine. I cannot see how this fate can be avoided as the power of our technology is rapidly making human effort obsolete. Indeed, the question arises as to what will people do with the leisure that would be allowed by the clever application of technology? Just live a life of idle dissipation?