alt Hacker NewsI don't think anyone has mentioned the obvious middle ground: PO Boxes at USPS post offices. Nearly every town and city in the USA has a post office. Instead of driving packages to individual's homes or having businesses deliver to their specific warehouses, the middle ground is to deliver everything to the USPS offices.
UPS, Fedex, and Amazon all use USPS for some last mile deliveries. It's usually a little less when using UPS and Fedex; not sure if Amazon bills less for it because I use prime shipping so the cost is hidden.