Isn't there a factor being overlooked here. I've been exclusively jpeg since I got the OM-1 and being a new camera I have shot many things that wouldn't normally interest me. For most frame fillers, jpeg is very good and I have no need for much editing, this includes, buildings, the garden, interior shots and even for my moth pictures jpeg results can be acceptable. The latter are normally shot in early morning light.
For planes which are usually shot nearer the middle of the day jpegs are often good but with any shadows really needing raw. BIFs are the big issue. I rarely fill the frame, contrast between the bird and the background is often harsh, shadow can be a serious problem and most of all It's not unusual for the combination of me and the camera to get the exposure wrong, often underexposing while sometimes over exposing.
I often wonder whether the people who say "I just try and get it right in camera" have ever shot BIFs where as well as the exposure, composition isn't always a luxury you have time to think about, especially if the background is frequently changing from dark to light and back again.
What I am trying to say is I wonder if there is any correlation between the jpeg and raw camps and the subject matter and light conditions that most interests them..