You could make many of the same arguments for Westerns: after all, you can have a Western Romance, or a Western Comedy.

So if Mysteries are "stories in which a puzzle is solved", and Romances are "stories in which two people fall in love", and Bildungsromans are "stories in which a young person becomes an adult"... why can't SFF be "Stories in which the contravention of consensus reality occurs"? It's a signifiantly more broad definition, but it does place specific boundaries. Can't that be a genre?