Bitcoin will only follow the dollar but will not replace the dollar, take the easy example until now there are still many people who make transactions using real money and still have to meet the second party without knowing how to transact via ATM, currently we are discussing about Digital money there will be more People Which will have difficulty in transacting.
Can't really say that what you are saying is completely true. Sure, Bitcoin does follow the dollar right now but soon enough it will be the other way around. What we are part of is not simply "Digital money". We are part of a revolution unlike any other where we, the people, take full control of our financials and put the power back to where it belongs. I certainly can't wait until the banksters on wall strett stop dictating what I can or can't do with MY hard earned cash. I can't wait until the day we see poor countries truly get the help that they need thanks to Crypto and Blockchain tech. You have to remember that Bitcoin also stops corruption more or less, both within govs. and banks.
I'll make a bold prediction and say that if we continue in the same pace we are today, in 50 years people won't talk about the dollar, or the euro or any other currency. There'll only be crypto and Bitcoin will be the at the helm.