Just looking at the state the world is in right now, it's easy to see why a lot of people are buying into this. I think around that time, possibly later, there is going to be some significant event(war, revolution, leadership changes....could be anything) that will change the course of history. Of course I don't look at it from the perspective of religious zealots trying to scare people with it, but with such high tensions between nations intensifying(look at us, Iraq, Iran, Pakistan, North Korea, etc) some shit is bound to happen eventually.