You response seems a bit confused/confusing, but the linked articles explain the situation fairly well. The crucial point is that AT&T/Cingular had a 5 year exclusivity deal from the very beginning. They were "on board", and indeed no other carrier could get on board. The initial terms of the deal were that AT&T gave Apple $10 per month for every iPhone user. Then the deal was changed to have AT&T subsidize $300 per iPhone, thereby lowering the iPhone price. In either case, every iPhone sold required an AT&T contract and was locked to the AT&T network.