No one can really say if when will all countries adopt Bitcoin or is it possible to happen because all countries have different looks at Bitcoin or cryptocurrency, some see it as a threat on the current financial system and there is a lot of competition while some countries wants to adopt it because of the advantages that it has. But there are different kinds of adoption, there are countries that allow the use of Bitcoin not to accept it as means of payment but to tax the traders on their earnings, while some countries like japan adopted it and now it is widely accepted in most of the services in their country. There are also some countries that haven't yet decided if they will legalize it and how they can regulate it.