It is said that bitcoin will destroy the fiat system but i believe that if this happens the world will change completly because banks and a lot of things will go out of market.
I do not think that Bitcoin is going to be used by every one in the future because many people are going to think I have no reason to make use of Bitcoin.
Most people just think that it is waist of time and that they can do better things with that time. I know this because I have talked to people who sad this.
Banks and other Investment Companies won't even be affected by the circulation of Bitcoin, and also do you think that a government's country will allow something virtual to be replaced their fiat money as their national currency? There are things untouchable until now and that is the currency system of the world. It is more stable and is accepted in your country not like Bitcoin where in my experience that it is not yet accepted by any local shops in my country. But I hope soon it will be accepted by everyone so that I don't get to keep converting my Bitcoin to Fiat.