yeah, local libraries would probably be better. Esp. with centralization concerns - too much power for a national postal service might be bad.
I *do* think governments have missed an opportunity to authenticate identity online. What if the post office (or library) had a way for me to establish my identity, like a digital ID card that I could use online when I need to prove who I am?
Right now, that role is taken up by credit card companies and email providers.