Losing the peg will be the beginning of the end, but the game might still take longer than you think to play out. For example if we know that we are about to be stripped of “AAA”, we can effectively default at that point and start over. The new rating will reflect the fact that we reneged, but so what? Also don’t assume that the Soviets and Chicoms will have their act together. Lots of things could go wrong in that relationship.
The “so what” part creates quite a bit of misery for a population whom only a scant few years earlier felt rich. I could say I have my back-up plans and “so what” also, but in the absence of a representative government, some of us must not be obtuse in our actions.