We had a UPS company rep at a local town hall meeting with our congressman about the postal service. He said that UPS would never want door to door delivery because the costs would be too high. At best he said they would make very limited rural route deliveries and continue deliveries to local post offices.
He said the cost of them delivering a letter would be a matter of dollars rather than cents unless there were some kind of subsidies paid somewhere.
I personally would give UPS and FedEx all the long distance stuff and ditch the big USPS distribution and sorting centers where the real costs are. Let the locals figure out how to proceed from there.