Verizon, Sprint Nextel, and T-Mobile - along with all their MVNO partners are about to see small chunks of generation X, Y and Z move over to AT&T wireless - who has the exclusive rights to the iPhone for the next two years (see Reuters article).
Worldwide cellphone sales are running at about 1 billion units a year, and Jobs noted that if Apple took a 1 percent market share in 2008, that would mean the company would sell 10 million iPhones.
Combine this figure with the corresponding churn numbers the other players will see, and you get one tough pill to swallow. Why is this such a big deal? Well, the difference between a 1% churn rate (e.g. Verizon) and a 2% churn rate (e.g. Sprint Nextel) is about a billion dollars in costs. Roughly stated, every 10 basis points is worth $100 million in costs. Yes, million.
Also, the hottest phone in the past few years was the razor. Sales of that unit are beginning to slow down. The market is demanding something new and hot - and there is not hotter brand out there right now than Apple.