I don't think that fiat will ever disappear in future as it holds support from the Government but same confidence we can't put on bitcoin as if it falls to extreme level then people may stop using it.
Confidence in fiat money? Lol!
Never in history of mankind were a government or bank issued currency able to survive!!Never!
Therefore I don't have any trust or confidence to our governments in terms of money.
And if Bitcoin should fail it will be replaced by another crypto coin with similar features, meaning open , decentralized and limited in supply!
So I'm not worried in the slightest of the future of crypto currencies.
Since 2009 we have to possibilty to choose between both worlds!! Before that we were trapped in this worldwide huge ponzi scheme.