USPS is a really well run service. They need to provide universal service, even to country folk at a loss, handle foreign parcels, etc. Most of their woes are created by a republican congress setting out a path for privatization. (Weather is next)

In terms of the self-reliant rural communities, you’re not factoring the very significant cost that the entire population pays to support your rural lifestyle. As agriculture continues to decline and consolidate, those externalities costs will continue to grow.