And I'm sure it's true, because no government has lasted forever and thus there's been no currency that's lasted forever. But so what? It's not like there's any guarantee that bitcoin has to hold any value whatsoever, much less be worth $60k/BTC. Do I think bitcoin is going to go to zero anytime soon? Nope. But I also don't expect the US dollar to go to zero in the near future either (though with all this money printing, I'd say it's getting closer and closer as time goes on).
US dollars and pounds are still better, although not possible for fiat to get to zero, but it can be almost worth zero. Even since some decades ago when some countries were colonized, especially African countries. Taking Nigeria that I know very well as an example, the value of Nigeria naira was stronger than US dollars at the time when they got independence and equal to British Pounds, but otherwise is the case now. Recently, the exchange rate of US dollars to naira is 380, we can see how Naira is almost worth zero if approximated. Some countries fiat currency are even worse as they were more devaluated over the past years. If the strong fiat like Pounds and Dollars are still having such issue, what are we going to refer developing and underdeveloped countries having. That is why it is just conclusive that fiat are not ways to protect someone funds as they are devaluating in design and controlled by the governments, although on purpose.
So to what I think about bitcoin, it is just one of the appreciative assets of today, people that are wise today are really moving towards buying such asset or go for good commodities like good. But as of present, bitcoin has been the most successful asset of last decade and possibly might be the most successful assets of this decade.