AT&T subscribers have remained loyal to the network following the launch of Apple’s iPhone on rival carriers Verizon Wireless and Sprint. “Churn has not moved at all,” AT&T’s president of emerging devices Glen Lurie told MarketWatch on Wednesday, referring to the percent of subscribers who leave AT&T to open accounts with other providers. In the years leading up to the iPhone’s launch on Verizon and Sprint, many AT&T subscribers had been extremely vocal about persistant dropped calls and other connectivity issues when using the iPhone in metropolitan areas. Some analysts speculated that the launch of Verizon’s iPhone 4 would send AT&T iPhone users rushing for the door, but that does not appear to be the case. In fact, AT&T recently announced that it activated more than 1 million iPhone 4S handsets in less than a week following the device’s launch. Lurie even said the iPhone 4S is selling so fast for AT&T that demand is still exceeding supply.