I am not certain about the iPhone upgrades, and i dont want to sound like an iPhone fan as i am not. It was just an example.

I would say it is purely a bug fix if the sole objective is to address phone bugs or even missing features, it is an OS upgrade if a key feature is adding APIs to allow compatibility with a newer standard for apps. I was under the impression iPhone upgrades have added APIs just as the computer os ugrades have. With computers, OS upgrades usually come at a cost and many people are willing to pay the cost.
I would have never considered paying for an upgrade to a symbian phone....but for the n900 and a new os version i would. I think there is a different dynamic here now phones are more app platforms like computers rather than appliances.

I hope Nokia either decide themselves or can be persuaded to change their thinking. They don't sound closed to the idea....just it is not the current thinking. But it should be understood by those reading this thread that Nokia has not planned to offer Maemo6 or Meego type upgrades for the n900 or any other past or future phone simply because there has not be a need before. Phones were primarily phones with smart features, not app platforms. New features didnt come from apps or software before.