Bitcoin can already be traded is all countries given a person has access to a device and the internet. It is some of the peripheral activities around it, like fiat onramps, where there may be more restrictions in some countries versus others.
It might be possible that majority are able to access Bitcoin as long as there's an Internet connection. But, I think we cannot guarantee that Bitcoin is accessible globally where some of the people are in the rare and far location from civilization. I guess the world will become 100% connected to Bitcoin more years from now.