Cryptocurrencies may or may not replace the U.S. dollar in future. Great economist Jerry Robinson made a statement, “Anything that challenges U.S. dollar dominance, is going to be heavily regulated”. For any kind of currency to challenge US Dollar, a necessary condition is that it should be the potential reserve currency. It simply means that the cryptocurrency would have to be held by central banks globally to pay global debt obligations. It indicates that all the possible commodities would have to be valued in that particular cryptocurrency, and not in US Dollar.
The actual negative point from the government’s side that could affect the usage of a cryptocurrency is the function of government to collect taxes as well as implement legal aspects in all the transactions. It would take too long, and never for a cryptocurrency to get a reserved and regulated status.
On the other hand, Cryptocurrencies are under-owned by investors. Approx. only 3% of U.S. retail investors have started using cryptocurrencies. It shows that we have just started using cryptocurrencies, though it has maintained a boom since very starting.
Only predictions according to current scenarios can be made, the actual vision would be shown by time only that cryptocurrencies would be regulated, diminished or continue as of now.