Just think how much the creditors are owed and what they will do about it if the US does not pay.

With massive military superiority I suspect you are in a stronger negotiating position than the creditors.  You can refuse to pay.  They cannot refuse to die.

And that is what will happen, because the debt is unpayable.

It's the lenders who will be the net losers.  Like a ninja you've lived in the Mc Mansion and urinated in the pool and let the grass turn yellow.  Now you just hand back the keys and it is the creditor's problem.