Losing the iPhone exclusivity might actually end up being good for AT&T. One possible mechanism to explain that:
- All their high usage, low profit (and vocal) iPhone customers go to Verizon.
- Their generally oblivious, high ARPU, low usage customers don't bother to switch... especially since their service will be much better after the high usage people leave.
- Their high-profit business customers get happier since they get the benefit of all the iPhone-driven network upgrades without actually having all those iPhones around to kill the network.
- They get a chance to throw marketing money at pulling in Android customers, which right now has a higher volume and better terms for carriers (better share of revenue, lower handset subsidy) than the iPhone anyway.
Of course it could also end up being awful for AT&T. Or it could wind up being generally neutral. Certainly losing exclusivity in the UK doesn't seem to have killed off O2.
To get a 'tectonic shift' I think it would be necessary for Apple to start selling unlocked, cross-network devices only with no subsidized options. But they have shown no desire to do that to date - they pretty much had to be forced to do so in the parts of the EU where it's a legal requirement.
That's not necessarily a good thing. Where the leaders of tech go, others tend to follow. Especially since in-network calling saves you on minutes.
The same is true of minute bundles. Users which go a lot over (and pay per minute) are fine, users which are a lot under (and still pay for the bundle) are fine. Users who are averaging use of 80-120% will probably be costing the provider more than they pay.
On Sprint and T-Mobile, yeah, we have unlimited data plans.
If Verizon were to offer the iPhone, a lot of the AT&T users with unlimited plans who are using a ton of bandwidth would jump to Verizon, and, if they were to try to return to AT&T, wouldn't be able to obtain an unlimited plan.