An alternative may be a much more valid reason than a replacement narrative.
The creators of bitcoin had an idea of why people should consider their product an alternative and we all know that bitcoin can provide something much better.
There are many problems with fiat currencies and we can see how economic developments are causing banking systems to become more chaotic and inflation is high, making currency exchange rates worse for some countries.
Money continues to lose value and is no longer able to maintain the resilience of a centralized system, but the economic journey is still needed by humans despite its weaknesses.
We don't know, maybe even Satoshi the founder has a narrative like that. You know, the reason why he creates a BTC is because maybe he hates fiat and wants to replace it by his own creation but if not, there might still be people who can think like that. BTC have already gone a long way, so why not right? Maybe we are truly heading on that direction?
But even right now or even before, we still can use our BTC as a main currency as long as we are on a country that allows it and even if not, we still can do bypasses and shop directly online using it. BTC has an advantage but it is not perfect. It has a disadvantage too and some people can consider it, resulting for them to not totally rely on the coin.