While it takes no great intelligence to follow a religion, I think it takes a degree of creativity to make one. In fact, some creative people have accidentally created religions (for example, Robert Heinlein accidentally created the Church of All Worlds by writing a science fiction novel) in recent history. Who is to say that some, if not many, religions were created by the tradition of storytelling?
Early man had little to do in his leisure time but to sit around the fire and tell stories. I think that storytelling, combined with written language may have made entrenched religions.
I don't necessarily think that the original storytellers behind religions had intentions of creating religions.
I think perhaps ancient religions started as just stories that grew beyond their intended scope, we'll never know but that makes sense to me. However, I also think that religion has been recognized as a political tool for longer than any religions currently relevant today have existed. I don't believe that the authors of the bible, for instance, would fall into the category of story tellers who had their message accidentally taken literally.