This might explain why Bob doesn’t like scary movies, as he reveals in the first episode. He lived one.
All in all, it’s a plausible theory and a great homage to the master of horror himself. I wouldn’t put it past the Duffer Bros to throw that in there as a little treat for the fans.
In any case, it might be a mixed blessing that Bob didn’t make it, because if he and Joyce moved back to Maine, odds are he’d end up at the tail end of Pennywise’s 27 year feeding cycle and he’d be hunted anyways.
Because Pennywise is always hungry.