This is why I thought putting the CyanogenMod installer app in the Play store was a watershed event, with Google acknowledging the role of aftermarket Android distros in keeping older OEM devices current. Too bad that didn't last more than a week or two.
The chart isn't entirely fair, since Google Play Services is a kind of overlay for some APIs that can be kept current without an OS upgrade. But that also has the effect of making closed some parts of the Android system.
Overall, Google could help enable, and could more strongly encourage OEM partners to provide upgrades. I'm not sure why that isn't a condition for Google logo and app suite licensing.
It might've lasted more than a week or two if it wasn't a warranty and support nightmare. The CyanogenMod installer app made it easy to install when it worked, but apparently it frequently failed leaving the phone as good as bricked for most users. (The only way to recover was to reflash manually using the traditional tools, and the app was aimed mostly at people who couldn't figure this out.) Also, it was a one-way trip - if users didn't like CyanogenMod or found it didn't run on their device, there was no way to reinstall the official firmware.
The chart isn't entirely fair, since Google Play Services is a kind of overlay for some APIs that can be kept current without an OS upgrade. But that also has the effect of making closed some parts of the Android system.
Overall, Google could help enable, and could more strongly encourage OEM partners to provide upgrades. I'm not sure why that isn't a condition for Google logo and app suite licensing.