there are already a number of other cytpo-currencies on the market,
Litecoin Novacoin, Peercoin, Namecoin, Feathercoin, Terracoin, Worldcoin, CopperLark, TagCoin, Devcoin, Megacoin, DigitalCoin, Freicoin, Goldcoin, Extremecoin, Anoncoin, Zerocoin, Fastcoin, Phoenixcoin, BBQcoin,YACoin, Ixcoin, Franko, CHNcoin, MinCoin, Timekoin, Bitbar, Junkcoin, Infinitecoin, Royalcoin, Betacoin, Rucoin, Solidcoin, I0coin, Tenebrix, Fairbrix, Coiledcoin, Liquicoin, and Smallchange.
None of them have the same value as bitcoin. why would any government sponsored coin be at all different. They would have a shorter blockchain, and would only be valuable in one country and be tied to one countries economy as well as their politics. It would have all of the draw backs of both bitcoin and traditional currency and few of the benefits.