I'm getting the idea from this thread that it's mostly the end-timers from Protestantism that are fueling this.
Yep, I bet you are correct.
I was Catholic for a good part of my life and when I was younger, I remember my oldest sister talking about how the end of the world was imminent when a Pope took on the name of Peter. I never asked her where she heard of this, but likely it was from other Catholics.