Now, maybe if you wrap your car around a tree and then have it repaired, they'll offer you a bit of a discount on the buyout.
If you like your BMW enough to buy it, there's a good chance you'll buy or lease a brand new one as a second option. As long as the profit they'll make from selling you a new car plus re-selling your lease turn-in exceeds the profit they'll make from you buying the car at the residual value, there's little reason for offering you more incentives to buy out your lease. Given how much used BMWs list for at dealerships, I am guessing that they probably want your lease-end vehicle back for resale, as long as it is in good shape.