very nice analysis Karen, as always !! As mentioned by you, I think key element (besides adoption in the cloud etc) here is the inter-change - how much can Issuers give in terms of rates, so that all parties feel that they are not losing .. how well developers adopt Apple Pay for mobile apps is critical .. there is one more segment that could be critical, besides Retail and Mobile, that is Online .. where PayPal is a dominant force. If Apple Pay can be converted, through a clever integration mechanism so that a consumer can pay his/her online purchases through Apple Pay, then they cornered the market !!