You shouldn't take a sci-fi writer's words as a prophecy. Especially when he's using an ingenious gimmick to justify his job. I mean, we know that it's impossible for anyone to tell how the world will be like after the singularity, by the very definition of singularity. Therefore Herbert had to devise a ploy to plausibly explain why the singularity hadn't happened in his universe.

I like the idea that Frank Herbert’s job was at risk and that’s why he had to write about the Butlerian Jihad because it kind of sounds like on the other side you have Ray Kurzweil, who does not have to justify his job for some reason.