When they really need to. But they'll fight it hard! Apple's business model is to lock everything down -- very closed indeed. This does not align with the goals of bitcoin, at least, how I perceive them.
tl;dr Apple = closed. BTC = open.
I think you are not making any good reasons why should apple accept bitcoin as payment. Anyways, apple will never accept bitcoin as payment because bitcoin is not regulated by the government, that is why there are only few stores which accepts bitcoin as payment.