While people try hard to pretend otherwise, nobody actually knows when or if AT&T will lose their exclusive iPhone deal, resulting in the iPhone heading to other carriers. AT&T has traditionally argued that whenever that day arrives, it's AT&T's network reliability that will keep people around -- a statement that's borderline hysterical given the last few years of complaints about AT&T's network in markets like NYC and San Francisco. With rumors of a Verizon iPhone heating up once again, AT&T's Ralph De la Vega is downplaying the threat of defections. Why so confident? According to De la Vega, 70% of AT&T's customers are on family plans, and it's annoying to move everyone and once -- and 40% of customers are on corporate discount plans, which are also difficult to dump. So should AT&T lose the iPhone, at least they can take comfort in the fact they'll retain the obligated and the lazy.