90% of those people should be writers and most want to be, but can't come up with a story they like. If you hate your stories, then your reader probably will, so they role play to get their writing fix to an audience that likes them. Or they do it for practice to sharpen their abilities. I write, if that clarifies things. Role playing on this one website actually helped me go more in depth on the detail for my own writing.

I have a hard enough time surviving this area :/