Re: android upgrade debate
For the developer it's about wanting to use the latest APIs, methods, and even the range of UI things you can style have massively improved with the newer Android releases. Alternatively you have to stick with the lowest common denominator, and 20% of a potential user base is not to be sniffed at.
Then there's testing. Testing requires a lot of effort- you cannot avoid checking on the multiple screen sizes and dpi, but then multiple API levels (more than the major Android release milestones), the multiple handset vendor customisations (I've had bugs that surface solely on Sony, and have one right now that only shows up on a Galaxy 3 Note) mean you really do have to test on more than the emulator.
That is, if you want to have useful, working apps on your Smartphone. Perhaps the majority of the Android user base is just happy with themes and spiffy looking program launchers?