Be careful not to confuse a local minimum of a function for a global trend. Google has mercilessly driven Android in the last one year (and has even promised to ease up) and if not for the rising trend of Android handsets, those manufacturers would be cursing all right. Also, those other companies you praise are also just as keen on leaving you in the dirt (see HTC Hero) or force-feeding you upgrades that you might not want (iOS 4 on the iPhone 3G). So sure, you can switch away from Nokia, but it's really a hit-and-miss of what you'll get, depending on where in the business/technological cycle you buy in to a particular platform/vendor.