The network effect only results in lock-in if there's an obstacle to using multiple networks at the same time. Obviously no-one is going to carry around two pho

The network effect only results in lock-in if there's an obstacle to using multiple networks at the same time. Obviously no-one is going to carry around two phones, so that's how Apple achieves lock-in. By contrast, keeping two or more messaging apps running is trivial. And SMS is irrelevant.