The real question is not how many years or how long will it take bitcoin to reach the number one spot in terms of currencies, the real question would be how bitcoin will achieve that, the reason why bitcoin hasn't reached the top yet is because it is still not legalized, governments and countries are not accepting it as a way for paying for things so people prefer not to use it, and major investors don't want to put money into it in fear of its instability, i think that if bitcoin gets accepted by all the big countries in the world it would defiantly reach the top and be used by everyone in the world for it is a currency full of advantages and benefits.
We have to give it some time, it is a new economic system and it is less than ten years old and we have to be proud of its growth in a short span, we really do not need government regulation to reach the trillion dollar evaluation, since the price has risen this much in a short period, the government cannot have a blind eye to this new economic market and so is the reason they are scrambling to come up with regulation and we had this rally because of big investment coming into bitcoin, if not we wont be in the two hundred billion dollar club.
I know bitcoin is new and it reached great goal till now and also about the market is very high.
But regulation is needed if we want to know bitcoin as mainstream to all people. Now bitcoin just being used for smaller community in all around the world. Government can help bitcoin grow much more faster.