What the fellow arguing Supply Side Economics re: 'the iPhone creating Demand' doesn't understand is that there was already a Demand for a portable computer before the iPhone was invented. He kept going on about 'his daughter could have stuck with a cheap flip-phone'.
But the iPhone isn't JUST a phone.
When Jobs and Woz invented the Apple II, it was the sixth or seventh attempt at making a computer people could own and use.
And people bought those weird early devices, some of which were just boxes with flashing lights.
Because there's a human Demand to be better organized and SMARTER.
Tap the Demand, get the features and Price correct, and you have a hit.
The Mac was an improvement on the idea; and again, it was a success, so much so that Microsoft stole the idea.
So when Jobs came out with the iPhone the caller's daughter immediately recognized it as something that satisfied her existing Demand.
Jobs didn't CREATE the Demand, he only DISCOVERED it.