[thayne]

1. FedEx and UPS are not at all competitive for delivering non-package mail (letters, bills, etc.). Or even small packages.

2. Commercial providers rely on USPS to deliver packages in some situations.

[eru]

About (1): you know that USPS literally has a monopoly and several legal advantages?

About (2): duh, yes, because they ain't stupid. For an analogy: if there's free municipal water, Coca-Cola would make use of that for bottling, too. Or if there were subsidised electricity available etc.