Hardware is different. Unless you specifically sign a contract like a lease that makes some arrangement other than the traditional you bought it, you own it scenario you can do whatever you want with a piece of purchased hardware. The have been cases in the past, for example DirecTV receivers where the hardware purchase price had a built in subsidy, requiring you to sign up for a subscription. When people started paying cash (instead of the usual credit card sale for a $300 item) and not activating the hardware (because they were easy to hack) DirecTV changed the way retailers were allowed to sell the hardware.
People keep getting the iOS software, and the related devices confused, thinking of them as a single entity. You own your hardware, but you don't own the underlying software. Among other things, the lawsuits targeted at the company that was selling OS X loaded on clone hardware (forget the name) also seemed to prove this out.