Ice Cream Sandwich is now installed on 10-percent of active Android devices, according to Google's own numbers. About 64-percent of users are still using Gingerbread. And the latest iteration of Android, Jelly Bean, is already on its way. When developers express concern about Android fragmentation, this is what they mean: Users are distributed over so many different versions of the OS that it's hard to develop for a wide swath. Not to mention that the latest and greatest updates take forever to hit the masses. [Android.com via Business Insider]
Does it really matter to the masses though? I really think this is a non-issue due to the fact that hte majority of cell owners could care less what OS the phone is running, as long as the phone works.
Maybe to us this might be a issue, but its smaller than we really make it out to be. For example, as an iPhone 4/iPad 2 owner, I am going to miss out on some of the features of iOS 6. I was kind of annoyed by it, but the millions of iPhone 4 owners will not really care about missing features, because their phone works fine. An I know the fact that these missing features are not going to hurt Apple's sales. I mean to be honest, I just upgraded my mothers phone to iOS 5 and outside of the notification tray, she still thinks there is no difference between OS versions.
More importantly, no one in your EULA on Android does it state you are entitled to a new OS for your phone. Until that changes, than this will always be the same. Since when we purchase a phone we are paying for that OS and that phone. Even the carrier contract does not state that we are expect to receive a new OS update over the life of the contract. So the numbers of users with the older OS should not be surprising to anyone.