Hmmm rural route carriers here are postal employees and either drive their own vehicle or a postal vehicle. And here(Iowa) is pretty rural. And they drive right up to the farm house to deliver packages. Must be different there. But here the USPS is required to service all addresses as required by law. UPS and FedEx are not. Hence , they drop ship to the local USPS to finish delivery, thereby saving themselves time and money. At the USPS expense
I think each state handles rural postal service differently-I don’t know who makes the rules-but they even vary from county to county here-some counties’ rural postal service doesn’t even deliver packages over a certain size-you have to pick it up at the rural post office...