Call it naivety if you will, but I don't think caveman beliefs will make a comeback anytime soon.
But yes, something could happen along someday that's omnipotent and not deity-based, I just don't see what the heck that could be. I mean, you take Q from Star Trek, he's omnipotent, but if he started wandering around Earth, teling people about everything that's going to happen, people would inevitably worship him and though he's not a god, it'd still be religion.