Here in sunny California where National Parks are close by and beach camping is plentiful, used RV's always sell quickly and are very hard to find both in great shape and for a bargain. The only RV's that remain on the used market here are really old ones that have been abused and even these sell eventually once the seller realistically adjusts the price.
All that said, nationally speaking, the economy is vastly improved, the job market is on the rise,and gas is insanely cheap and predicted to remain so for a while. I saw a report stating that sales of large cars/suv's has increased dramatically recently thanks to cheaper gas and a better economy. I would assume that will also effect the RV world as well.