Is the USPS a Natural Monopoly?

Just thinking out loud, but is mail a natural monopoly?

The U.S. Postal Service has seen a precipitous drop in volume lately.

So they raise their prices, making other alternatives more attractive, which further depresses volume. It sort of looks like a death spiral.

Of course, "mail" can mean messages, so email is a functional substitute, as was facsimile.

And mail and packages can be delivered by any number of competitors (FedEx, UPS and others). To the extent that FedEx, UPS, the Internet and other alternatives aer widely available, perhaps "mail delivery" is not a natural monopoly.

Still, without large subsidies, the network is not profitable. It could not provide universal delivery without subsidies and it certainly does not ever make money. So it is one of the other models one has to look at when thinking about the future of the communications network business.