How many miles have you been able to get on your tires?
My car has 19" Pirelli PZero run flats. Currently at 16k miles and they look like they're barely half worn down. At this rate I don't think I'll have to replace them until 25k miles. One rear is almost brand new as it was replaced recently under warranty due to road hazard. I keep the pressure at 36F/38R, and it does feel slightly harder than the recommended 34/36. This may be responsible for the long tread life. LA roads aren't that smooth and I drive it pretty enthusiastically. I peel out on the turns now and then and once even did a 180 burnout! Still holding in there way better than I expected. I do mostly short distance city driving.
2013 750i Mineral White
2011 750i Jet Black
2007 750i Monaco Blue