I once encountered a reddit user vocally insisting in a regional subreddit that industrialized society would collapse in the next 10-20 years. I poked around his comment history and it was non-stop commenting in /r/collapse pondering the kind of collapse that would happen, theories as to what would trigger it, and plans for how they would somehow survive and turn it into a utopian society for themselves. Like 9 months of this kind of commenting. The kicker was a wall of text, a dozen paragraphs long, about how he'd emerge from his bunker and become the patriarch of the local group of survivors - ultimately leading to him having several wives, of course.
While there are pressing challenges like climate change, aging populations, inequality, and more, I find that the substantial majority of people who devote large amounts of energy towards pondering and preparing for the collapse of civilization are using it as an escapist fantasy. I see lots of parallels with people preparing for Judgement Day: some unprecedented event is going to kill off the majority of the population leaving a chosen few to inherit the new world. These collapse predictions are often rooted in serious issues, but I find that this kind of escapism makes the average person more skeptical of serious activism.