The Mortal Engines Quartet

One of my old favorites that I first read several years ago is the book series The Mortal Engines Quartet by Philip Reeve (published in some regions as The Hungry City Chronicles). The books take place untold thousands of years in the future, when human civilization as we know it has ceased to exist following a cataclysmic war between hyper-advanced societies and weaponry, and new ones have sprung up as humanity recovered from the disaster. Due to the now-unstable weather and ecosystem, most of the world dwells in massive mobile settlements called Traction Cities, adapted from formerly motionless communities (the first book begins in the moving city of London). Technology and science are at an approximately 19th-early 20th century level, with things like heavier-than-air-flight and digital computing lost to history. The advanced future people are referred to somewhat reverently as "Ancients", and their technology is considered the stuff of legends, with artifacts and fragments highly sought after.
This is an example of apocalyptic science fiction (or, more specifically, post-apocalyptic). It's a rather broad genre that generally involves the end of the world as we know it, and frequently explores the changes and hardships brought by whatever ended human civilization. This kind of story has grown especially popular in recent decades, with video games such as Fallout and films like Terminator (nuclear war and machine uprising, respectively) and shows like The Walking Dead and Defiance (zombie pandemic and alien invasion, respectively). What do you think is driving this particular interest in end-of-the-world scenarios?