Personally,
I hate that genre, though it doesn't mean I don't watch it....
I think you have the wrong premise. I DON'T think it has anything to do with the viewers apetite for realism.
REALISM HAS NOTHING TO DO with Reality TV!
In fact, it's the least real!! think about it: "14 studs and babes stranded on an island, each week voting one off in a democratic fashion.." In all of mankibnd's history, wehen did anything remotely like that ever happened?!?!
I think it's the viewer's apetite for VOYEURISM, not realism that has us all drowning in reality show.
I'd even go as far as saying it is the viewers' lack of resistance to voyeurism, rather than apetite. We simply can't resist it. Obviously, the opportunity to peek on others without their direct knowledge is imnpossible to resist for most of us.
And the TV industry capitalizes on this more and more....
As for myself, I really hope they will move on to the next new thing already... :-)
hope this helps...