I mean, I suppose Congress could stop printing dollars. But that would cause the mother of all financial meltdowns, so I'm thinking no. And that wouldn't leave crypto in charge, either
As far as I can tell, the basic positions on crypto in America are 1) it should be eliminated, or at least highly regulated (for instance, so that people have to pay taxes on their gains) and 2) do nothing and let crypto keep pulling in suckers. Thiel etc are scared of position 1.
Crypto is not a currency, despite the name. At this point in existence, it's just a highly levered NASDAQ tracking index. Its correlation with tech stocks is very high, which is sort of the exact opposite of what its proponents think it is and the exact opposite of what you need from a currency. There are lots of different "coins," which means that any crypto takeover would have to decide which of the coins to adopt and which to jettison, and of course there's nobody in a position to make that decision (one could say let the market sort it out but the only way that has ever worked in the past was serial bankruptcies). There's no monetary authority to control the supply of crypto coins (the limit on 21 million bitcoins is actually no limit at all because they are fractionally divisible), and while the crypto idiots think that's a feature, it's a huge bug.
So, no, I don't think any crypto takeover is on the horizon. Not as far as the eye can see. Lots of things would have to happen to make that a reality, and most of them are bad. Some would be "world falls apart" bad. The irony is that if anyone did try to replace the dollar with, say, bitcoin, bitcoin's value would plunge to zero because the first effect would be to create a massive financial crisis, and in crises, investors run to safety. Which isn't fucking bitcoin.