I think that bitcoin is far from the point that traditional fiat currencies will be disrupted. The market cap for the Dollar is in the tens of trillions of dollars, while bitcoin is well under 10 billion.
It's surprising how quickly alternative technologies / new and more useful services can accelerate and threaten the dinosaurs of the marketplace who refuse to change or adapt. BTC, although still small, has achieved moderate but important levels of awareness, acceptance, retail adoption and positive government interest. Yes, it's got a long way to go but it's less and less likely to go nowhere with every day.
The snowball effect has yet to kick in - when it does, voters will eventually realise that QE is debasing their buying power and bitcoin/crypto is an answer. A Tipping Point can happen well before market caps are equivalent - it's a people thing.