Of course this comes with its own set of gigantic issues, likely triple digit inflation and hardship to raise money for generations.
But US can't default really.
Debasement is far more painful - the treasury will simply choose not to come good on the obligations.
Credit worthiness is a must and you're talking about the savings and liquidity of all the world, us citizens, banks and institutions included.
There's a reason Germany and Italy can borrow lots of money at relatively low costs despite everything: no matter the economic crisis, no matter the inflation, no matter if the countries were in rubbles post not one, but two world wars, they always paid their debts.
I'm not sure how can you imagine that defaulting can be anywhere better than increasing inflation.
And the US in particular has the huge advantage of being able to mint the money to back it.
It operates under expectations - the more liquid the asset, the more likely you'll be OK with accepting it in the context of a trade. The discount is for illiquidity.
I'd love to see someone buy a TV with those bonds.
It could. We'd just reorganize and call the old debts part of "Old US". This is all "New US".
Some use gold or minerals. I wonder if this is what US does. Also this makes me think why every European countries are taking their gold reserves out of the us.