That only makes sense if I'm comparing Apple to Google. I'm not. Fragmentation is a fact of the Android experience. It's part and parcel with the model that Google and the device manufacturers chose. Arguing that Android has quick update ability while ignoring that those updates aren't made available to 95%+ of Android users is completely disingenuous.
And how about iOS "fragmentation"? The iPhone 3GS and 4 are not getting the best new features of iOS: Siri, turn by turn navigation, Flyover, 3D Maps, FaceTime over 3G, etc.
iOS gets much more updates, yes, but the features old devices are getting are pretty little: VIP mailbox, Facebook integration, dismiss call with SMS, new redesing stores, new Safari features, etc.
Its better than nothing, obviously, but people make it seem like iOS updates brings all of the new features to old devices. Ios devices only recieve one full update and the next ones are partial (which makes you need to upgrade if you want Siri and all).
Ipad 2 has not get Siri for example. And iPad 1 doesnt receive any updates after only 2 years (and it was a premium product).
Is iOS 6 the same in the iPhone 3GS, 4 and 4S? Nope. I would call that fragmentation too. Apple tries to force consumers to upgrade to the new iPhone just like other manufacturers such as Samsung, HTC, Motorola, etc.