I will agree that most coins aren't backed by much, but it only takes one. There are certain coins out there at this point that cannot be 51% attacked even by nation-states, coins like BTC/DOGE/LTC. The hashrate is simply too large at this point and the networks are too global.
In any case, there comes a point where the government has no choice but to monetize the debt, which leads to hyperinflation. We saw this many times in the past.
When you're spending over 90% of your tax income on interest payments, you will turn on the printers. There is no choice.
Previously, the reserve currency would just switch places. From the Netherlands, to the British, to the US.
But previously we didn't have a trustless solution. There was always some form of counter-party riks in the past. Crypto has no counter-party, and so you don't have to trust Russia or China or anyone else to somewhat manage the next reserve currency.
There's going to be a number of different things happening at once.
For example, one thing I fully expect are "trills" - shares in GDP. Think of them as a debt-to-equity swap of the economy. The one major terracore advantage of a trill-based economy instead of a bond-based economy is that recessions aren't as brutal. This is because the value of a trill goes up or down with GDP, meaning trill holders don't benefit during a recession. Contrast with a bond, which typically goes up during a recession.