Dunno how true but I was told that the lease companies have something similar to GAP insurance to cover the difference between the residual and what the car sells for at auction. That may be why so few of them are willing to negotiate the residual at lease end.
The fact that so many end up at auction and go for so little allows the Used Car Dealer to sell them so cheaply. Those low prices attract new buyers, thus expanding the user base. (Silver lining in Dark Cloud.)