All the worry about if and when the N900 will get Maemo 6 is really a non-issue. And comparisons to other OS upgradeablity are out of whack with reality.

The iPhone can - so far. At some point - likely very soon - that must change as newer versions of OS-X become unusable on older hardware. For instance, the original iPhone can't run 3G due to hardware limitations. The iPhone OS upgrade train will inevitably come off the tracks.

As for Android, already some phones running Android 1x are unable to upgrade to Android 2x. And OS updates that have been released are causing many apps to break. Compatibility issues with apps on various versions of Android has become a serious headache for developers.

You're making assumptions. That has not yet been determined.

There is no such 'rule'.

That may be a possibility.

But regardless of whether or not the N900 ever gets Maemo 6, it will have little impact on the value or useability of the N900. From a post I made in another thread:

"Maemo 6 apps will be QT-based. But QT 4.6 is ported to Maemo 5, so most (if not all) Maemo 6 apps will run on Maemo 5. So Nokia's plan is...the N900/Maemo 5 will continue to be able to run new, cool stuff for a long time, even if it never gets the 5-to-6 upgrade.

Nokia (qgil, actually) has already publicly stated - here in this very forum - that right now, Nokia has more than just bugfixes already in the works for Maemo 5 and the N900. Speculate all you want as to what those improvements might be and when they will be implemented. But the point is that more is definitely on the way for the N900. It has not and will not be abandoned anytime soon by Nokia.

Now, given all that, where's the problem?"