I think the only regrets are from Sprint Customers. See this link to their own internal forum. Over 800,000 hits and counting...users are upset over their network.
I believe that the published agreement was for 30 million iPhones over 4 years. If you do the math, that comes out to be about 1.9 million per quarter (16 quarters). Not a very good start. So far, they are 0 for 2. You are right, the next 2 quarters will probably be even less....followed by a decent quarter with the LTE iPhone. But then again, Sprint cannot compete with the big dogs (AT&T, Verizon) when it comes to LTE. I'm not very optimistic on their...
Sprint was "first" with 4G...WIMAX...what a mess...they are now abandoning it.
Verizon was "first" with 4G LTE.....again....a mess...4 national outages since December. Also, they are focusing too much on the map....and not on the backend connections. Hence, latest PC World Tests are already showing AT&T's 4G LTE as faster:
Apple has no right to control what prices a supplier provides to other customers. If they want a supplier to be exclusive, fine. However, Apple should not be able to interfere with other supplier contracts.