Remember the "paperless office"? Didn't happen. Actually, paper use increased. But the prediction wasn't completely wrong, just mis-focused. Actually, a lot more communications without paper happened; paper just didn't go away as a result.
Voice control will change things a lot and will become widely used in important ways. Will they make keyboards go away? Not for me and lots of other people. Can't you just see 20 people in a meeting all talking to their computers while the presentation is going on? I can't. I can see people saying to their dashboards as they drive someplace: ' "Message to Ann P - bad traffic. will be 20 minutes late. see you then." Send.' (BTW- the message service will see that Ann P is connected using her mobile device and has an email account and will send the message to both, as optioned by the sender.)
I think better writing while not talking. I think lots of people do. Will that change more toward voice control? Probably, just because it will be available. Will silent manual input of language become obsolete? Maybe, when brainwaves can drive text input. Hey! Maybe text will become unnecessary by then, too!
PS: MacWorld reported that MacAlly's new $100 BTKeyMini keyboard will work with the iPhone when it comes out this month. We'll see...