Don't be silly governments use gold to back up their fiat currencies and the governments will never accept Bitcoin and especially not to back up their existing currency. Gold will always be of value and used in modern times.
Yes that is right that governments are not in the favor of bitcoin and most of them are favoring gold and fiat for their state but as the time passes they will know that bitcoin is a currency which has more power than any other currency or any other asset so in the future it is sure that bitcoin will replace gold in hat matter.
Make no mistake governments hate gold as well, since gold makes them accountable and they cannot spend as much money as they want and they cannot print as much money as they want, that is the way the gold standard began and how it ended, countries felt restrained by gold and they began printing currency lowering the amount of gold they needed to hold for each piece of currency they printed, eventually they abandoned gold and created fiat.