In the next 100 years, do you think Governments will create their own cryptocurrency or digital currency that will replace fiat currency, i.e. coins, paper money, the paper dollar, etc.?
If it does happen, will it be like bitcoin or will it still represent gold like how today's money works?
I think no, government need money that they can control so create decentralized currency is very big mistake. The velocity of money will affect the country's economy so if government cannot control the number of money that spread in the market then it will become big trouble. I learn about it in my university.
Yes, governments will always support their national money.
And they can have various forms - cash, non-cash, or their various combinations. Governments can also issue their own centralized cryptocurrency, which they can fully control and interact with their own money. However, even its own cryptocurrency is unlikely to ever replace cash. Maybe in three hundred years ...