Depends. Where I live outgoing mail goes into the closest blue USPS bin. And given that most days all mail I receive is slop, removing the slop would remove the need to come to my house.

Of course, where I live the USPS person stops in a general area and does all the outgoing deliveries on foot, but it's conceivable that some days an entire block may receive no incoming mail. Also, we need to take into account things like fuel costs for planes & such throughout the entire supply chain.