I've shared this idea with newbie lucid dreamers and they've had similarly realistic results, so I don't think I have any particular expertise here.

It's a good theory you suggest that the realism kicks in because I'm concentrating on the scenery. However, it generally still holds even when I turn my attention to the dream content. It doesn't always hold -- like if I get caught up again in some dream plot. But there are certain kinds of experiences that actually reinforce the realism, like what I mentioned about contact with dream-teachers.