Perhaps you haven't noticed, but Apple has pretty much always only made a few of anything.
A few products-- iPod, iPhones, computers software, services.
A few lines -- Apple TV, Mac Mini, MacBook, MacBook Pro, Mac Pro, Mac Servers
A few SKUs in in each line -- entry, mid, advanced, pro
One OS (with slightly modified for Server, iPhone, iPod)
A small number of shared component families,
This is not just an esthetic or a marketing strategy (although its that too) its a...