I'd be quite interested to see what the International breakdown of those 7 million iPhones are. Because the iPhone is available on a lot more than 1 carrier. (And it is available for the other 5.7 billion people in the world.
http://www.telstra.com.au/mobile/phones/iphone/
http://www.optus.com.au/iphone
http://www.vodafone.com.au/personal/iphone/index.htm
https://www.virginmobile.com.au/shop/iPhone.aspx
http://www.three.com.au/iPhone?intcmp=W0001
Or you can buy unlocked direct from Apple:
[1] T-mobile are being acquired by Orange so whatever they say about anything is subject to change... Can't imagine their new overlords will be happy about them dragging their heels.