Whitefur
Dreamer
I agree with you, UnionJane. Some writers, even the famous ones, tend to make their fantasy universe a changed version of our world rather than create something more out of the ordinary. One of the things which sticks out REALLY well is that everyone prefers horses as mounts for Riders. God forbid they can ride on anything else than horses. But the reason they do it is not lack of originality, but public preference. Like you said, we got so used with the world we live in and its rules that we tend to question and comment something that abides by said rules. I'd tend to say that it's like some universal rule: write something not-so-crazy and get your story going rather than risking the dislike of your readers. And this is more simple than coming with all sorts of explanations.