Audio only FaceTime calls in iOS7. You know how text messages automatically switch over to your data plan or WiFi in iMessage? Imagine the same thing happening when you make a call. Result: a cell phone that comes with free / free-ish calls. While AT&T and others continue charge three different rates for calls, text and data Apple is making the distinction obsolete.
Apple is going after the cellular market.
Make no mistake - if Steve Jobs and Steve Wozniak were teenagers today - they'd be on the short list at Department of Homeland Security and labeled "terrorists" and "extreamists".