Thoughts?
Who said that it is necessary for bitcoin to become a cryptocurrency which will be used in every single country at the world, as a main payment option. I dont think that this is even possible, because many reasons (market cap, as you have already said) for example, as far as we know only Japan government wants to adopt bitcoin, but other countries for now have not chosen.
Anyway, any country won't implement bitcoin as a currency because of one extremely important issue: they cannot control the emission of this crypto, and they basically cannot influence it in any way except through the market.