Would take way more than one letter to make USPS profitable.
Their core business has been declining for the past 20 years and business mailer lobbyists work very hard to keep the current price caps. This idea that we should let the finances spin out of control and raise taxes is a recent idea.
Standard communication (including addressing) is such a basic, critical function of government that it only makes sense to do it at scale and just fund it with taxes.
Your approach leads to exploding federal budgets, which are already the bane of the US, Canada, and the EU. When will you learn? Everything is not the exception, everything is the problem.
When will you learn? Taxes are not “the bane” of the EU, taxes are why It’s a nice place to live and America isn’t.
Speaking for a patchwork of samples that have fascinated me in the U.S.—New developments tend to incur impact fees to offset their immediate effects on the roads, sewers, and sidewalks. Police charge a fee to connect your alarm system to their dispatchers, an hourly wage for an off-duty cop to stand guard at your commercial premise, and a fine if you waste their time with false alarms… in some cases they attempt, at least notionally, to recoup the cost of the investigation from criminals upon conviction (I hear the collections rates are unimpressive…). Heck, some places bill inmates for each night in jail! [0]
Fire services tend to send you a bill for a false alarm, a fee for an inspection and, if you did it on purpose, a criminal charge plus the full cost of the response. And lord forbid you accept EMS services…
All are tax-funded, but all gesture at apportioning costs in relation to use. If they send this much junk mail while it’s quarters-a-pop, how much would they send if it were free…
[0] seriously! https://www.flsheriffs.org/uploads/Subsistence%20Fee%20Final...
Maybe some amount of messaging connectivity, for a narrow set of cases like court summons and other official messages, could be run as a public service at the taxpayers' expense. But likely the bulk of it should be run as a paid service, either regular businesses, or/and non-profits that still are expected to break even.
However municipalities should be allowed to, not forced to [or not].
Comparing today to 40 years ago: as far as I can tell, letter mail is virtually always used for the purpose of transacting business these days. Forty years ago, it was used for business and personal purposes. If I wanted to communicate with family on the other side of the country, it was more likely than not done by mail. Even 25 years ago, a long distance call took some thought because it was charged by the minute. These days, at least in Canada, all but the cheapest of mobile plans comes with nation wide long distance and we have the Internet. Both services are available for less than basic phone service back then.
Parcels are a different story. I can't guess how people's personal habits have changed, but the business front is very different as far as I can tell. Mail order was the exception in urban areas back then. It would have been different in rural areas, but in my explorations of the country I discovered that some towns were places where people lived while other towns were regional hubs for businesses. There would have been some mail order and a lot of doing without, but I suspect it has seen a shift where proportionally more parcels are commercial in nature. On top of that, the standards for delivery have changed. When I was a kid, it could take weeks to receive something via the postal service (from across the country). Now shipping times are more aligned with couriers.
I realize there are economic benefits to subsidized mail, but I'm not sure that subsidizing businesses should be a priority.