This is NOT a zero sum game. That is an oversimplification which doesn't conform to reality. For example it could be used in a basket of currencies as a world reserve currency which might make sense. Its about diversification, and not putting all your eggs in one basket. For thousands of years there have been many different currencies. There are many different scenarios which could play out. You have no clue what will happen to altcoins since no one can predict the future. You don't seem to believe in freedom of choice, which is autocratic. This is the OPPOSITE of freedom, or democracy.