You'll get the same problem with windows mobile, have you ever been able to upgrade any mobile from one version of windows mobile to the next? Even if you could for one, can you do it for all?

Also I doubt that given the number of n800/n810 users that support will stop.
For browsers fennec is coming and should help a lot.
For email there are many choices.
If your not happy, just sell it now and quit whining ;-)