We all remember cryptocurrency. Everyone in tech proclaimed fiat was dead, every office buzzed with talk of every possible way that cryptocurrency could be used, billions of dollars flooded in to projects losing money hand over fist. The cynics reacted to the froth with outright rejection of the idea. And today… cryptocurrency exists, it has some use, but it didn’t take over the world, it didn’t kill fiat, it was use…
Cryptocurrency is more popular and intertwined with the financial system than it ever was so while the claim isn’t currently true it doesn’t mean it won’t be on a long enough timeframe.
If you are old enough then you would be aware that similar claims were made about email but only one country that I know of (the Netherlands) no longer processes mail. Still if we had to guess I would say that we are still early and email will replace the worlds postal systems.