I recently had someone tell me they didn’t think they’d be interested in The Succubus Gift because they were tired of books about demons. So am I, along with a number of other things. There aren’t any demons, vampires, shape shifters or other paranormal creatures in my books. Such topics have been worked almost to death.
The large publishing houses classify books into genres so they know which editor to send them to. It’s a mailroom thing. A book that crosses genres, or an entirely new concept, doesn’t have a mail slot.