I agree with you. Folks who like organizations/clubs/heirarchy/ego-trips/etc are attracted to S&R, and most of them are mediocre (if that) climbers. As you said, there are a few really good climbers in S&R, but they are a minority.
My understanding is that the Mountain Rescue organizations are volunteer, so they take what they can get.
If the few (and the modest) uber-climbers such as yourselves don't join, then Mountain Rescue is composed of the folks who do. Such as Mounties and NOLS graduates.
And they will go out there and do their best. Because if they didn't go out there, no one would.