I think there is a glimmer of potential with something in the piece that got me curious.
At one point XM inrduced an antenna that had the chipset embedded in it. This enabled the end user to use the antenna on XM enabled devices.
If Sirius XM were to market a docking station that housed the satellite chipset and included a SDARS antenna, then the iPhone could literlly become a defacto satellite receiver and decoder of sorts. This means that the cost to the company to deliver the service is substantially less because of rayalties. For the consumer, they are not eating up minutes on their data plan unless they undock.
IMO, the pain here is the coordination between the iPhone and the dock. A consumer would not want to buy two subscriptions (one for the dock, and another for the iPhone). If through software they can marry an iPhone to a dock, then we can see the consumer only needing to pay the $16 per month, and get the best of both worlds. Full satellite feed in the dock, and great internet feed out of the dock.