People are absolutely obsessed with Apple products. Whenever they release a new product, people line up and wait hours for it. It doesn't matter to Apple fanatics that the item they are waiting in line for is eerily similar to the one they already have, they just want the new apple products. People don't realize what goes into the launch of these products at Apple retail stores.
In the back of the stores are plastic storage bins and containers that are filled up with the new items. For the sake of this article, let's pretend we're discussing the launch of an iphone 5. The first thing that the stores should do is locate the bins that have the accessories inside of them. Grab all of the accessories and start unloading those first, as you don't want people to buy the phone and not the accessories. Once you unload all of the containers with the USB cables and screen protectors and cases, next you can start to worry about the phones.
Most stores will have the different models packed in different bins. So you'll have one container with all of the black 16GB phones, one with all of the white 16GB phones etc... This makes it easy to to set the store up in the exact way that the manager wants.
So by using some efficient and economic storage bins, Apple is able to easily roll out their new products and avoid complete chaos. The only chaos they have to worry about is angry customers that waited in line for way too long!