I don't think that it would be possible in future, even though cryptocurrency has been used by so many people around the world, even though it is really helpful for everyone who is using it, it cannot still be a standard currency in the future because as what we all know it is decentralized, which means it cannot be handled by the government and its volatility makes it not suitable to be used for daily lives.
I think cryptocurrency is only good as an alternative currency for fiat currency, it is meant to be converted to fiat currency whenever we want to.
I agree, maybe bitcoin as we know it will be the BASIS of whatever currency we wind up using down the line, but I do think that whatever we end up using will be somehow referencing BTC (i.e, it won't just use "the blockchaiN", it will be built on top of the actual bitcoin blockchain but be much more scalable).