The way I think Jobs does things is he has an idea.. in this case it is the touch tablet. The touch tablet is the be-all end-all. It is the holy grail device in a line of devices that starts with the iPhone.
The iPhone is like the lowest end version of the tablet. But Jobs starts with the lowest end because if you bought the tablet you would have no need for the iPhone really.
So I think the tablet was the real focus all along.. but Jobs is going to sell the least desirable one first (the iPhone) knowing that people have no choice since they have to buy it.
I think it worked the same way with iPods. Jobs stated with the most bare bones iPod imaginable. All it did was play music. No other features whatsoever. Now look at the iPod. It's a full fledged media device. Jobs could have come out with the full fledged media device first. That was the real goal all along.. but he sold every device imaginable on the way to that in the process. I think they are doing the exact same thing with the tablet. The tablet is the real device everyone will want. But he is going to make us earn it essentially. Because we have no choice.