Under simplified circumstances that question is easy to answer: Early adopting countries will win over late adopting countries, because Bitcoin's price will rise during adoption. Any central bank could buy a huge slice of Bitcoin's total monetary supply for chump change today. The risk is small, but the reward could be astronomically - imagine what would happen if a central bank would make an announcement of having purchased Bitcoin... it would be a bold statement of trust and would lead to prices skyrocketing, accelerating further adoption. The first central bank to do that will make a very smart move.
In the extreme long term anything is possible. What I don't see that clear is countries giving up on having a say on how they issue their currency. Then again, it's not like European countries have a say, at least half of Europe does what Merkel wants anyway.
the problem of poor country to take advantage of bitcoin is that for the fact that they are poor, they can't build a good infrastructure to support everything that could benift their activity if they were using bitcoin instead of their currency
instead country that are advanced and have not economic issues, could build a side by side structure that help bitcoin to growth, they don't need to replace fiat, they just need to support those that in their country want to choose bitcoin
and it is not a coincidence that the countries that are adopting bitcoin the most are in fact rich countries(maybe there is some exception...)
Is it really so simple?
I do understand that initially the countries with high financial abilities will embrace it, even if the government does not, the people will surely. This does make it seem that such countries will prosper most and benefit most from bitcoin.
Supposedly as time passes only the third world countries are left without wide bitcoin adoption. But as time does pass market forces will work towards ensuring that bitcoin becomes adopted, International Trade for one will, and the mindset of people in such countries will naturally be to prefer payments in the global currency, Profit seekers from the first world and second world countries can then offer to take services and pay in bitcoins.
The second limitation the infrastructure is being bypassed quickly, African countries show how efficiently mobiles can be used for btc, and it is set to develop.
What I seek to say is that as time passes Bitcoin will be adopted throughout the world not limited to technical constraints.
Here are where things get interesting,
Now bitcoin enables each country to earn as much as it has the capability to, the endowment of it's natural resources and the efficiency of it's human capital, will determine it's financial prowess.
Which is unlike a situation that exists today with economic dominance through finance control that exists. The banking on US $ being the reserve currency and each country have to convert to US$ for International Trade. Giving US immense power to arbitrarily balance it's trade payments.