Think of it like this, death is unpreventable and we still live our lives. So even if the world collapse was totally unpreventable (I think we can still turn it around), it's still better to go down fighting and living life.
Looking at it now, I think doomerism, preppers, apocalyptic religions and the guy that stands on the street shouting "it's the end of the world" are all a basic part of the human experience. It's not a coincidence every cult eventually reaches the narrative of the impending end of the world.
Death is suppressed and finds other avenues to pop out in