Apple has always done this.
The original iPhone, and the iPhone 3G had identical processing hardware, yet iOS 3.0 added MMS, tethering and stereo Bluetooth features to the 3G.
iOS 4 ran on both the 3G and 3GS, but home screen backgrounds, limited multitasking, game center, personal hotspot, even something as simple as new text tones were restricted to the 3GS.
Siri was restricted to the iPhone 4S and iPad 3, despite the fact that the year old iPad 2 had the exact same processor, but even higher clock speeds than the 4S.
iOS 6 ran on the iPhone 4 and 3GS but only the 4S got 3D maps and turn by turn directions and several other improvements.
And every car manufacturer ever, TV manufacturer, video game console maker, and on and on and on … has given newer models newer features. It’s called giving people a reason to buy the newer things.
People here act like Apple is a public utility. It’s not. It is a for-profit company, and the name of the game is to get people to buy the stuff they make. Everything else they do…everything…is in service of that objective.