I wish I had saved the article but I remember reading somewhere (and just paraphrasing here) that the team that works on the iPhone make it good enough so you'll use your iPad (tablet) less, then the iPad team makes it so good you'll use your MacBook less, and so on. I think it's great forward thinking to be always trying to put one of your largest product lines out of business as a way to constantly innovate. In so doing, you hopefully have less chances of having to lay off tens of thousands of people because you tried hard to stay ahead of the curve.
Unlike Apple, Kodak was caught in a very hard place. With film they would collect revenue for every picture taken, through the film itself, developing, and printing. With digital you could make money on the cameras themselves, but your per-picture revenue opportunities were limited - this was the great attraction of digital. It's not the same as Apple replacing devices one-for-one.
