It's also much easier to release updates when all devices that run your OS are consistent, or at least largely homogeneous. Android smartphones have so much variety, both in terms of features and technical specifications, that it must be difficult to have updates released so quickly after Google pushes out a new version of the AOSP. AndroidCentral had a good article about this several months ago (link: http://www.androidcentral.com/why-you-ll-never-have-latest-v...)
I know one will argue it's not a viable solution for the 99% of Android phone owners out there, but the modding community for Android is very quick to update most flagship phones on most carriers, and even develops on phones that carriers have stopped pushing updates for. My Galaxy S1 had Ice Cream Sandwich on it when I finally traded up to a Nexus 4. It's not as convenient as Apple releasing the official update and rooting+customrecovery+clockworkmod+customrom is a process complicated enough to bar many people from entry, but for those capable folks, we can get updates almost as quickly as those on the Google flagship phone-of-the-day.
I know one will argue it's not a viable solution for the 99% of Android phone owners out there, but the modding community for Android is very quick to update most flagship phones on most carriers, and even develops on phones that carriers have stopped pushing updates for. My Galaxy S1 had Ice Cream Sandwich on it when I finally traded up to a Nexus 4. It's not as convenient as Apple releasing the official update and rooting+customrecovery+clockworkmod+customrom is a process complicated enough to bar many people from entry, but for those capable folks, we can get updates almost as quickly as those on the Google flagship phone-of-the-day.