Volume rather. People are having MB of network traffic daily coming out of their prepaid plans. Oops. Phoning home is expensive with smart-phones. People really should consider the OS they run. Does it work for the user or against the user? Free Software works for the user, a big plus. M$, on the other hand has honed the art of getting others to labour for M$ for free, providing IT support for their buggy software, re-re-rebooting, fighting malware and phoning home (WGdisA etc.).
UPDATE Perhaps the market knows. Android Phones beat iPhones in USA. At this rate, Android phones will out-sell RIM in the next quarter. Whimpy Phone 7? Down 1.8 % points. 2011 is going to be another great year for Android/Linux. I can see it spilling over onto all ARMed-thingies.