I agree with your sentiment, but
- The Openmoko phone is 2G while the iPhone is 3G.
- The iPhone has a camera.
- The iPhone is cheaper, if you're prepared to sign a contract. (On the other hand, if you just want the hardware I think the Openmoko phone is cheaper.)
- The iPhone can actually be used as a phone if you "dual boot" into the Apple firmware. I'm under the impression that the Openmoko software stack is barely capable of this at present though of course the position will improve.
No doubt similar comparisons can be made between the iPod Touch and things like the Nokia tablets.
The fact that people are prepared to go to such lengths to modify their iPhones shows how much value they put on the hardware features that it offers. Openmoko (and anyone else) have no choice but to offer the same or preferably better features, if they want to get very far.