the government of every country should give legitimacy to cryptocurrency. Has already given legitimacy from many countries.
Not as easy as you say every country must exercise legitimacy against Bitcoin, if all countries / governments are united there may not be war in this world, one word.
That is the problem, in a multi-head country, not all heads think the same, including to exercise legitimacy against Bitcoin, they know Bitcoin is the biggest asset for every country through transactions, what to say.
There are many pros & cons to legalize, to state and to make decisions on state policies, let alone Bitcoin, It is very clear that only pro-people countries do Bitcoin as legitimacy, if the state is not pro-people, don't hope.
In fact there are also countries that do not prohibit and do not order people to use Bitcoin, but Bitcoin there is growing faster and growing.
Not only that, during the last century we have seen a tendency of the governments to try to get more and more control of the population and while this is something that governments have always wanted, thanks to our advanced technology of today this has become a reality, and bitcoin with its ability to give freedom to people is challenging that control, as such governments do not want to legitimate and legalize bitcoin on the eyes of the people and I think this is going to still be the case for a long time.