I don't think the case is as simple as either you or Icahn present it, but you leave out two factors.

First, the pressure on merchants to buy new credit card terminals just now (by October 2015) is pretty serious. Merchants who hold out are faced with the entire EMV fraud liability for payments on non-EMV equipment.

Also, I'd expect the bulk of Apple pay business (by far) to be the online component, on iPhones and iPads.