I agree, we should just realize and agree that universal postal service cannot be profitable and accept the cost (tax), like we do for military expenses for instance.

Having said that, having a universal postal service requires physical presence in lots of remote areas. And those remote areas not only lack postal service, but also banking, tax services, and even why not grocery shopping. I do not see why we could not let the postal service provide those extra services, especially in the remote areas. People in big cities would likely have a different bank, they have access to a DMV near by, or supermarket. But, in a remote area, how a retired person can cash his social security ? renew his driver license ? Maybe there is a "service" opportunity that would make those remote post office more sustainable. I do not see why the postal office could not provide other services especially in remote areas where they lack. The physical location of the post office becomes a more valuable asset.

I think the idea that there needs to be a philosophical line drawn is a fallacy. We could simply do things we want and not do things we don't want on a case by case basis.

Not sure what the philosophical argument is, but it sounds like we're using artificially inflated prices (due to lack of competition) in urban areas as a sort of roundabout way of providing mail to rural areas. The comment to which you replied seems to suggest that it's better/simpler to just provide loss-making mail services to rural areas funded through progressive taxes and be done with it, like we do for other services we deem socially necessary (military, education).

What's wrong with a government-run grocery store? I can quickly think of a hundred reasons why I would support such an idea. And no reasons yet why I wouldn't support it. But you make it sound like a government-run grocery store is massively crossing a line for you. So I am curious about that.

The GP was justifying USPS's monopoly on first class mail. A government-run grocery store sounds pretty great. A government-run monopoly on grocery stores...not so much.

For reference, the US Government runs thousands of grocery and convenience stores via the US Military exchange (PX) and commissary apparatus. I remember these stores being a fantastic benefit of being a Navy brat.

The structure also hints at problems with government run businesses- the PX system avoids all sorts of sales and property taxes and gets reduced or free rent. The commissaries do that and get direct subsidies as well.

Before any service members (or their spouses) go after me, no, I am NOT arguing for any change to the system, just pointing out how existing examples look and work.

I don't know that that is a fair comparison because many of these stores you can't access unless you have a military ID. The prices are subsidized as well.