I have full fenders on mine... only rain maybe 10% of the time. Do you stop hard a lot? I've been trying to avoid doing that lately.
I commute in Arizona, so I think that is a big part of it, and having to do minimal maintenance in general since there is less slop on the roads. I don't stop hard too often when I anticipate traffic lights, and I have been known to only slow at stop signs if there is no traffic coming. When I try to make a personal best time though I run the brakes a little harder, just to keep the average speed up. I probably only have about 10 complete stops on average though over about 10 miles.
Maybe I just ride too slow to wear out pads as often as you guys?