iTunes was already in place, so the infrastructure and payment methods already existed. TBH this is only something Apple can answer. I think you're right that

iTunes was already in place, so the infrastructure and payment methods already existed. TBH this is only something Apple can answer. I think you're right that Apple don't change tack due to pressure. However the iPhone was a volatile product, with a high risk of failure. It also ran the risk of getting booted off carriers for abusing network, and runs all sorts of security issues... remembering in an abstracted way its hooked to your bank account.. to your personal finances. I mean the last thing Apple needs is a porn dialer and malware problem like Android has got. I would say they had plans to do the App store all along, you'd be foolish not to at least explore the concept. They where already doing games and little things for the iPod, so in a sense it already existed. But I bet there hand was forced... or maybe the carriers hand was forced letting Apple win the argument... by public pressure and hackers already writing there own code.