I think they should have expansion ports to add on certian fucntionalities such as HD, hard drives, etc, and make boards go together really easily to where the retailers could just put the boards in the cases themselves, or figure out somehow to make it simpler, or make it plug into the receiver for the hard drive or something like that.
If they gave everyone a pvr unit then that would cause the price for each one be a FRACTION of what it would be if not everyone would get it. They could give everyone a second tuner in the receivers and it would not cost that much extra as well. They would probably try to keep their price down though.
Also some customers will probably be keeping those receivers they have now since they would be compatible, especially considering all the new receivers being made now are compatible for both services.