One possible counterpoint: each major cell service provider is angling to have its own snazzy smartphone. Verizon/BlackBerry. AT&T/Apple. T-Mobile/Android. And now, Sprint/Palm. If you assume that this isn't just a short-term fluke but actually represents some kind of long-term force to be reckoned with, we may well see all of these platforms around for a while.

WinMo and Symbian? Not so much, at least in the U.S.