I don't think it will be possible . Making bitcoin world's currency is a very risky step and no government will agree to take this step . Bitcoin is highly volatile , its value decreases and increases which can really effect a country's economy . Moreover bitcoins are not centralized so there will be no limitations on its uses . Bitcoins also does not supports any taxation which is the main reason that will not allow it to become a world's currency . The anonymous identification property of bitcoins will lead to growth in many crimes . So it is not possible.