Having the latest Android version is starting to mean less and less
Saw this article on Android Police and how they explain how Google is circumventing the slow adoption rate of the latest Android version by instead putting more of their updates in Google Play Services (which every Android device uses, despite that device's Android version). This, along with the fact that most of the core Google apps can be updated on their own, shows that one doesn't need the latest version of Android to experience the latest Google has to offer. This chart:
is starting to mean less and less, which is a good thing.
Unfortunately, the biggest drawback to all of this (and will forever remain a drawback) is earlier versions of Android lacking APIs from later versions. Unless Google starts putting new future APIs in the Google Play Services APK instead of part of the Android framework itself, this problem won't change anytime soon.