Do iPhone 4/4S sales actually result in significantly lower profits for Apple? Those devices are sold at $200 off or $100 off the price of an iPhone 5, and I would imagine the cost of manufacturing the older devices must have dropped significantly by now. (the iPhone 4 is going on 3 years old at this point!)

Also, one would expect a drop in sales of the '4S' (or '3GS') model when the "completely redesigned" iPhone 5 (or iPhone 4) is announced, relative to sales of the iPhone 4 when the 4S was released, or sales of the iPhone 3G when the 3GS was released. The release of the iPhone 5 makes the 4S look especially old, while the release of the 4S didn't really do that for the 4.