That's irrelevant to this discussion. Google doesn't make the Android versions for each phone manufacturer and carrier. It provides an open source software that each company does whatever they want with and it's their sole decision whether to upgrade their customers or not.
A better chart would be of the Nexus phones since Google actually makes those phones.
Whoa. That's the biggest load of bs I've heard in a long time XD
Take a good look at the chart. Why do you think about half of Android users are still on dinky-stinky old Android 4.4 and below, which is already discountinued?
Why are there so few only on Android 5, which came out two years ago, and much less even on Android 6, which came out one year ago? Let's best not talk about Android 7, which came out over a month ago, but so far has been spotted less than the monster of Loch Ness XD (Now compare that to the adoption rate of iOS 10 right now).
For those a little slow on the uptake, the answer is very simple: All manufacturers have to purchase Android from Google. There's actually very little they can customise, and with each Android version, that becomes even less.
They further have to purchase any and all updates and fixes for all Android versions on all devices they have from Google. That's why you don't see that much updates for lower-end versions, it would simply become too costly for them with Google's greedy money-grubbing prices, which rise more to the ceiling all the time. Especially with new Android versions, prices for manufacturers are getting more and more exorbitant. On top of that, it takes a ridiculously long time until new Android versions become available for purchase in the first place.
Source code for Android also takes a long time to become available, and it comes with a huge disadvantage: it's entirely unsupported in any way, and you won't see any updates for it, at all. Basically, you would have to take it and start to create your own Android fork from scratch. Without any help from Google about how things work etc. Google wants to sell their Android packages, nothing else. So you'll have to find out everything on your own, all by yourself. You'll have to put an absurdly immense amount of money into a huge software research & development facility to get your Android fork off the ground, all by yourself, with no help whatsoever. It would take a year, at the very least, until you have a half-way workable and usable version out.
In the meantime, the competition in the fiercely contested Android market would be lightyears ahead of you, using Googles pre-build Android packages. It would take several years until your own Android build finally starts to pay out, and until then, you'd only have massive losses. No manufacturer in the Android market can afford that, not even the biggest one, Samsung. So they all purchase the pre-built packages from Google, even if they have to pay heavily through the nose for them, as well as for any and all updates, and the prices only get ever more wicked with every Android release.
