There are 2 different metrics and I think you effectively shift from one to other as it suits you..

Metric 1: They provide an efficient service. Posts reach on time (rain or shine), they have systems and process that make the organization not waste effort.

Metric 2: They earn more money that what is spent by them.

By metric 1, postal service, railways and public transport in most places, a large part of governmental services (DMV), medicare in US are efficient. Depending on your neighborhood, even police, fire and ambulance are efficient.

by metric 2, most government services will not be efficient.. however, the government is not a business and I would argue that because people confuse 2 with 1 is why US does not have a better quality of life. The job of government is service using tax dollars.

Take public transport for example. In my mind, it should be mostly subsidized and effectively free. Trying to make it a profit center makes it a "non-public" transport and you end up with limited services which has secondary effect of reducing mobility and restraining the economy.

It's a service. The US Highway system runs at a loss too if you treat it as a business.

I can send a letter anywhere in t he country for 58 cents, UPS or Fedex would charge $10?

Of course it runs at a loss. It’s a public service funded by taxes.

The military also “runs at a loss”—should we expect it to be profitable?