Can't really speak for dealers, but i've had mine for sale for over a month now on autotrader/forums and get nothin but blind lowball offers (25k? Really?) from people who don't ask a thing about the car.
It surprises me to hear things about them not lasting long on dealer lots.
Do people just prefer the ease of buying from a dealer?
Personally, when i buy used i prefer private party as i feel if you have a problem car, its easier to dump as a trade in to a dealer than sell it.