They obviously don't represent workers. The USPS is one of the last big organizations where normal people can expect to have a retirement plan, even if they're disabled.

In February, 250 UPS workers walked out for 90 minutes to protest an unjust firing. UPS told them to keep coming to work, but every week they would randomly fire 20 of them until everyone was gone to give the company time to replace them. After months of campaigning against it, the workers got off with 2 weeks' suspension for what they maintain was a legal protest.

But the incident is indicative of what we might expect in a completely privatized parcel delivery industry. If the workers hadn't been unionized Teamsters, UPS would have probably gotten their way. This is the kind of working environment a lot of people in Congress are pushing for.

http://www.businessinsider.com/ups-reverses-firing-of-250-wo...

Yes, the rules established by Congress in 1792. I don't think anyone would argue that organization has much in common with the current Congress. No organization in the world other than the USPS is forced to pre-fund pensions with $5.5 billion annually. Imagine if Amazon.com had to play by those rules.

Also, I'm not convinced by your argument that a $66 billion/year organization is going to fail because their trucks aren't big enough. The USPS actually carries a lot of packages for UPS and FedEx.