" "End times" types have been around since I was in college. In one form or other, they've been around since the beginning of Christianity. As Asimov put it, it's been 2000 years, and they're still waiting. Psychologically, it's comforting for some people to believe that some wonderful outside force is going to come in before it all hits the fan and Fix Everything. If it isn't Jesus, it's space aliens."

It's older than this, for instance the Chinese/Indian thought the world went through cycles of destruction, so it's easily 5-6 thousand year old belief. And of course Christ was the saviour as foretold for about 1000 years before he showed up {though of course the Jews are still waiting}.