Neither of these two is correct.There really are two things that matter to a fiat currency's survival in this world:
1. How big the military is backing it.
2. How much Debt that country is in.
This is a libertarian lie used to sell gold, silver, to fund raise for politicians, to sell survivalist food, etc.The debt is really getting bad, bros. For all 3 big currencies in fact, the USD, the Euro, and the Yen, they are all in epically shitty shape! All 3 Printing at record levels while their economies wither. All 3 Printing just to pay off the interest on their debt, never the debt itself. All three doing advanced Keynesian borrowing tactics that tempt fate daily. ALL THREE OWNING A LARGE CHUNK OF EACH OTHERS' DEBT, TOO. Shit's going to be bad bros. Really, really bad.
Professional fund managers who handle billions of dollars in wealth don't believe this is inevitable or even likely in the short term. These are people with skin in the game, who are very keen to watch for this sort of catastrophic event.
The libertarian math is, what goes up must come down. Which is great if we lived in a world where the value of the dollar wasn't subjective, but based on objective balance sheet truth.
But we don't live in that world. We live in a world where the stock market crashes every two years, and people climb right back in until the next crash.
And so I think it is most likely, that if the USD survived the end of Bretton Woods, and Ron Paul freaking out in the 1970s, until now, there is a pretty good chance that the dollar will last another 40 years (Lindy Effects).
That said, if you want to use this as your shill hustle for Bitcoin, worried that the value might drop if people on WF aren't buying them, then go for it.
But I think, if you really want to be an advocate of Bitcoin, you'd get off this forum and go stand on a street corner with a sandwich board sign and reach the every day man.