I'm not so sure we are seeing an increase in false prophets. Charlatans like Camping have been predicting the end of the world forever. Camping himself predicted the same thing back in 1994. Look up date setters and you'll see a long and rich history of these types of con men.
Yes, one day we will have an increase in false prophets, but I don't think that time is now. Camping is just a run of the mill lying hack, and his followers are gullible fools who are so desperate to believe the end is near that they will trust almost anything he says. Human nature is what it is, and this type of thing has been the norm throughout human history.