"They keep their prices artificially low to keep the competition down, and at the end of the year they run billions in deficit."
I.e. affordable.
Its called a public subsidy; something in times gone by was considered an essential, and not so ruinously expensive service that should remain within the public, and not the private, domain. Hence it was the only federal agency explicitly authorized in the Constitution.
It was just too important to leave the prices of postage in what are in effect, unaccountable private hands, whose only inherent preoccupation is to their quarterly profits.
As for the deficit, is was in fact due to decline in mail volume as a result of increasing use of emails and the internet in general for business transactions and correspondences. But it was also due, in part indirectly, by that relentless sequestration that became the driving mania of Republican in the past six years.
Has nothing to do with competition, in fact UPS, Fedex and many other minior courier use its tax funded delivery points in more remote locations.