A country that issues its own currency never has to default. The only question is does the country produce enough goods/services that the rest of the world wants such that the currency (or its debt) stays in sufficient demand.
The above goods and services can simply be “stability” relative to the rest of the world, such that wealth seeking a safe haven continues to choose assets denominated in they nation’s currency.
The above goods and services can simply be “stability” relative to the rest of the world, such that wealth seeking a safe haven continues to choose assets denominated in they nation’s currency.