Bitcoin can not end any currency, since bitcoin is as yet very little famous among us. Half of the world doesn't know what actually bitcoins is and those who know about bitcoin accuse it of a scam. Also, how would we purchase bitcoin if the cash gets end?. We won't be able to exchange. For me, dollars or any cash ought not to end. It might make a few issues and hurt the bitcoin itself as well.
Even if the whole world knows about bitcoin, there isn't enough for everyone and bitcoin has a big shoe to fill in if it were to replace dollar as a standard reserve currency for many countries, many will try to accumulate as much and there will be not enough bitcoin to go around. We need to realize that what we are asking is impossible to be honest, bitcoin replacing dollar is BS because bitcoin hitches its value on dollars.