I agree that you should base your purchasing decision based on what's available at a time of purchase and to not assume too much of what new fixes, functionalities and extensions that are promised to become available for said device.

BUT, it's not unreasonable for someone who's shopping for a new phone to compare the N900 with other devices in its price range/advertised functionalities: Blackberries, Androids and iPhones AND to learn that ALL of them provides OS upgradeability. Especially with N900's much touted opensource lineage.

To deny this claim sounds... a bit narrow/short sighted apologist talk to me.