But that's because people moved on the newer devices. The only way a device can truly die is if people move on from it. Even if the n900 gets MeeGo-Harmattan, people will still move to the new and shiny.

Look at android for example. The Droid will get 2.2 but I've heard a lot of Droid owners say they'll be getting the EVO 4g. The Nexus One is getting Froyo first but isn't stopping people from ditching it when the Dell Streak comes out

The only reason you are still using your pentium II is because you are attached to it and have chosen to not move on. But most people from that era have. There's still support but you don't see a pentium II enthusiasts forum anywhere