I wrote the piece / did the research. Happy to answer any questions or comments people might have.
It's an apple fanboy piece, presenting heavily skewed data, be it from either straight-out falsity or improper definitions: 1) Original iphone can't run iOS 4, but it gets green all the way through. Similar issues with 3G and iOS5. EDIT: I see now that the way you've done the timelines makes it confusing, and seems to be done intentionally to make your point rather than clarify what's going on. 2) 2.1 to 2.2 is a min…
For example, Android 2.2 added huge performance gains, which definitely makes a difference for what app developers can do and what you can run. It also added very useful new features like wifi hotspot that make the device much more useful.
Meanwhile 2.3 had a streamlined UI theme and added a new keyboard, NFC, gyros, WebM/AAC, multiple cameras, etc. Is that just minor?
As an Android user, I feel the graph is pretty representative of the ecosystem and how my experience compares to iPhone users around me.