Chronologically.
Nov 11 is not 11th November, it is November 2011.
May 12 is ... ... you get the picture.

So working your way down the list starting from #1, is the list of events that would happen. Basically you buy a droid-phone on 24month contract and in that period you need to get at least (min) two updates. The first is to have the latest build when you buy the phone and the second must be anytime in that 18months to keep it on the latest build. After that I think its fair if they drop support as that last 6 months will give carriers "breathing space" and give consumers an incentive to upgrade.

Basically following a systemetic structure like that, enforcable by Big Goog, would make developers use new toolkits for apps so that they function better. Half the apps I have are built on the 2.1SDK and my phone runs 2.3.7 which has a lot of speed improvements. No wonder the iPhone is buttery smooth compared to the average android phone.