Apple doesn't 'depend on AT&T'. They're not locked in beyond a short-term contract. They're using AT&T because it makes financial sense - they have a sweethea

Apple doesn't 'depend on AT&T'. They're not locked in beyond a short-term contract. They're using AT&T because it makes financial sense - they have a sweetheart deal in the US. Worldwide, they use a whole bunch of providers. When they decide that sticking to AT&T isn't in their best interest, they will switch to a different provider.