If they can fork Bitcoin to their liking while not destroying its major selling points, more power to them and I'll even invest in their fork, but I don't think that's possible. The changes the government would demand would make it orders of magnitude less valuable and most of the current economic majority would stay with Bitcoin Classic. They could grow FEDCoin larger than Bitcoin, more valuable, etc., but Bitcoin would still have its uses - precisely those uses that were neutered in FEDCoin.

In summary, government-sponsored forks aren't a threat to Bitcoin. In fact they would probably just help, because they would get the general public familiar with the ins and outs of crypto, such as security. Then there's Bitcoin with its ex-hypothesi better features.