Having the iPhone 4S on Sprint and Verizon hasn't led to customers jumping ship from AT&T, the latter's Emerging Devices head Glen Lurie said in a discussion Wednesday. Churn, or the turnover of old customers leaving for new ones coming in, "has not moved at all" since mid-October, he told MarketWatch. AT&T has had relatively low churn since the iPhone arrived in 2007 and has usually seen a significant, though not majority, amount of iPhone users coming from other carriers.
