Android 5.0 "Lollipop" was released about half a year ago, and while its adoption rate was much slower in the beginning, it has now spiked to almost 10 percent of the Android market, according to the latest platform distribution numbers from Google.
Google usually releases a major platform, to which it gives a dessert-themed name, and then iterates on it with bug fixes and a few minor feature additions. In this case, we have "Lollipop," which includes Android 5.0 and the recently released Android 5.1.
There may or may not be an Android 5.2 as well, depending how big of a change Google plans for Android 6.0 and whether it needs to delay it in order to implement those major changes. However, chances are that Google is now trying to keep a major-version-per-year schedule, and it should release a preview of Android 6.0 at the next Google I/O event, while the stable version could arrive late fall this year.
Until then, we have only Android 5.0 and Android 5.1 (Lollipop), which currently represent 9.0 percent and 0.7 percent of the Android market, respectively, for a combined total of 9.7 percent. That's definitely nothing to be proud about, because it could be years by the time the vast majority of users are on the Android 5+ platforms. By then, 10 percent of users could be on Android 8.0.
As we can see in the distribution numbers chart, Android 4.1 (Jelly Bean), which was released just about three years ago, still only has 15.6 percent of the market, and there's no reason to believe new versions will transition more rapidly from Android 5.0 in the future.
Because Android is open source and because so many (essentially) OEM-tweaked "forks" of it exist, a "clean" upgrade path is almost impossible. To have a clean standardized update system would mean all the OEMs would have to agree to abide strictly by Google's guidelines for what they can and cannot modify on the platform.
However, as soon as Google tries to do something like that, the OEMs usually cry foul that Google is making Android more proprietary and restricting what they can do with it. Google may also not want to upset the OEMs too much by forcing a unified update system on them either, because of the fear that those OEMs could take their business elsewhere, as it were.
When we look at the matter practically, though, we see that some have already tried that (Samsung with Tizen), and it hasn't worked very well. The reality is that Android and iOS are so entrenched in the market right now that it's hard to believe a significant third platform could arise on mobile when it comes to apps.
Even Microsoft, after spending billions upon billions trying to make Windows Phone popular, has essentially admitted failure on the app store front, and is now trying to make Android and iOS apps work with Windows instead. This strategy isn't too different from how BlackBerry adopted Android apps on its platform because it also knew it had no chance to build a strong third app store. Trying to build a new app platform from scratch is an insurmountable effort. Google shouldn't be fearing it so much, even if the OEMs threaten to do it.
As for OEMs starting to adopt Windows on their phones because Google would force a unified update system on them, that doesn't make any logical sense. OEMs may have other reasons for the switch, but the unified update system wouldn't be the real reason, because Windows has even stricter platform guidelines and its own unified update system.
For years, Apple has made fun of Android and its fragmented update system, and it will continue for years more. Microsoft has recently started doing the same. The update system on Android is something Google can ignore no longer, and it needs to do whatever it takes to fix it. Otherwise, it risks having users (slowly but surely) switch to more secure platforms that do give them updates in a timely manner. And if users want those platforms, OEMs will have no choice but to switch to them too, leaving Google with less and less Android adoption.
Google also can't and shouldn't leave the responsibility to OEMs and carriers anymore, because so far they've proven themselves to be quite irresponsible from this point of view. At best, we see flagship smartphones being updated for a year and a half, and even that is less than the time most people keep their phones.
Even worse, the highest volume phones (lower-end handsets) usually never get an update. If they do it's only one update, and it comes about a year after Google released that update to other phones, giving malicious attackers plenty of time to take advantage of those users.
This update "system," if you can call it that, ends up leaving the vast majority of Android users with security holes in their phones and without the ability to experience new features until they buy new phones (which is sadly a kind of planned obsolescence as well). This can't be an acceptable state of affairs for Google, and it shouldn't be. Google already has a great six-week update system for Chromebooks, and it's time to have Android catch up to that, as well.