There's a couple problems with that idea.<p>1) It requires the US government to run the payment network. That's an expensive and security sensitive installation. The government, by far and large, isn't terribly good at running IT installations (see, the recent healthcare.gov)<p>2) The governments like to exercise capital controls. They do that way of the banking system. If it introduced digital $, they can't control it. Because anybody with a wallet could receive and spend them, assuming that everybody can create a wallet.<p>3) If not everybody can create wallet, i.e. the wallet needs to be governmental registration, it puts further demands on the features of the IT installation of the government. This isn't making it it any more likely to happen.<p>4) The credit card and banking industry would feel themselves threatened. Because, a lot of what they do would be taken over by the government, there'd be no end of political flamewars and stalemates trying to get this trough.<p>5) You're assuming that the government running the payment network would somehow, magically, be better than credit card companies. I very much doubt that, transaction fees would probably be even higher, and reliability would probably be pretty miserable.