i think no government are qilling to back bitcoin, they will for sure create their own cryptocurrency rathern backing someones currency, but the good thing is they can selfregulate cryptocurrencies just like what the japanesse givernment did right now, its a very good move as cryptocurrencies were meant to be self regulated and japan was the first to implement it
Yes, I agree with you, the government is not possible in a country to make bitcoin centralized, but the government might make their own cryptocurrency. So it's really what you say, that the Japanese government is not fully controlling bitcoin, but just making rules for bitcoin users, it needs to be sampled by other countries.