People don't lose faith in fiat, because the government uses its muscle to ensure that they continue using it. Long before Bitcoin, there have been ways for people to stop using fiat - they could have used gold instead. But even in countries with hyperinflation, the government machinery has ensured that fiat continues to be used.
Fiat has no equal at this point in terms of usability and relative stability. I see no reason for anyone in a stable country to use crypto over fiat, and I don't see it change in the foreseeable future.
Those in unstable countries will obviously need an alternative, but I'm not sure if crypto is that helpful to them. I have been to South America a couple of years ago, and most local stores were literally begging me to pay in USD.
The currency that people here dislike the most is offering more usefulness than crypto at this point. Crypto enthusiasts can disagree with this all they want, but there is no other way to put it.