Hypothesis:

The fascination with cataclysm, end-time scenarios, apocalypse etc during the late phase of civilization doesn't appear because people are more afraid of such events, but because they unconsciously hope for the end to come.

They just can't take it any longer.

And who could blame them? Imagine another decade or two of constantly growing corruption, incompetence, idiocy, degeneration, perversion, war, crisis, tyranny…