The technological strides are quite significant. Conceptually though you are absolutely correct, the iPhone concept is Apple's current hammer. I'm just surprised at how effective it's been. For example, they successfully bludgened the netbook market with the iPad even though people clearly prefer a keyboard in front of their 10" screen... even when it is an iPad. I suppose the concept is flexible enough for people to make it work even wjen it's not ideal for the job. It remains to be seen if they can keep up in wearable computing with that attitude.
That was my point. Jobs refused to make one though and up until the iPad Apple insisted that an iPod touch was a much better device for the niche. They found their hammer with the touch screen rectangle and so far things have been similar enough to nails for it to work.