That is absolutely wrong. Every single day I speak to a person who lives in an area where the Post Office doesn't delivery. They have to drive to pick up their daily mail at a PO BOX.
The customers tell me, "the Post Office doesn't delivery here." In 3 years, I've had maybe literally maybe one or two people say FedEx didn't delivery and those were to weird places like inside large universities or park systems.
You are absolutely 100% incorrect, that is a fact. I deal with this every single day.
R E A D. I said "service" every address. USPS does, by law. FEDEX doesn't.