Bitcoin remains to be adopted by every country in the world for various reasons. Here are my thoughts on why..
1. Government policies: Most government and financial institutions round the world seem not to want bitcoin cause of the financial freedom it gives to its users. They would want to control and tax the flow of finances of individuals and they probably fear the anonymous nature of its transactions. Some policies even go as far as criminalizing its use.
2. Scammers and fraudulent practices: Scammers have found bitcoin as a safe haven cause of its transactions being anonymous. Also, terrorist groups among other sources get funded by bitcoin also cause of its anonymous nature. Fraudulent practices and transactions are made with ease wth the use of bitcoin.
3. Fluctuating value: The value of bitcoin isn't steady as it rises and falls. The uncertainty in the price and value greatly hinders the general adoption worldwide.
4. Awareness: Nearly not enough effort on creating and spreading positive awareness on it as some government and individuals alike is hell bent on spreading negativity around and poisoning the minds of prospective users. People need to be aware and understand what bitcoin is really about and be awake to its uses.
5. Information hoarding: You could get lots of information about anything on the internet including bitcoin. But the internet can be misleading to newbies cause you could get right and wrong and also misleading information on the internet. It puzzles me that people with an in depth knowledge of bitcoin would purposefully hoard and keep information to themselves. You may think people don't hoard information but in reality, people do. It irksome just thinking about it. If people could share information, newbies won't readily fall prey to scammers.
These are my thoughts on what's preventing bitcoin from being adapted worldwide.
You miss one thing - there are already existing currencies and payment networks that do the role that cryptocurrencies are trying to fill. Like anything, for a new improvement to come along and dislodge an incumbent, it requires a big benefit over whatever already exists. Now Bitcoin can fit that bill, but it seems like the amount of power required to run the overall system, the ability to expand to cope with the huge amount of transactions that are taking place and the ability to complete transactions instantly are all hurdles that still need to be overcome. I think Bitcoin has a little niche to fill - moving larger amounts of money across borders, but for day to day activity it seems far off the mark.