Apple is rumored to announce not one but two new iPhones on september 10. One of them will be the new premium iPhone (5S). The other will be the "cheap" one (5C).1
It will be a big change in the current manufacturing strategy of Apple. Nowadays, there is three iPhones available: the flagship — the iPhone 5 —, and the older and (slightly) cheaper iPhone 4S and 4.
By releasing the 5C, Apple can get rid of the iPhone 4 and 4S once and for all. It means that there will be only the iPhone 5C, the iPhone 5 and the iPhone 5S. Doing that was probably not possible for Apple before, without compromising the quality of the cheapest model and at the scale at which Apple operates.
We can infer (if the rumors are true) that Apple has now the production lines to release two new iPhones at the same time.
This has a big impact: In the fall, all the iPhones sold are going to be capable of using every features of the last OS. It's huge. For example, iOS 7 AirDrop only works on one current model: the iPhone 5.2
It can put the iPhone way ahead of its competitors that struggle with OSes versions and hardware disparities.
It will also unify the lineup around the new lightning connector and the 4 inches screen.
It implies that the hardware and the software are going to evolve at the same pace.
The story is the same with the iPads. I am almost certain that the iPad 2 will disappear this year, leaving only the new Mini and classic iPads available.
The next year eventual iPhone five inches will fit perfectly in this new strategy: selling only renewed devices with state of the art hardware and software.
Update: Related, "It’s the Production Line, Stupid".
Update 09/12/2013: Guess I was wrong. The new lineup is made of an iPhone 5C, 5S and the old 4S.