What prevents government from paying their bills, rent and loans forever? Warren Buffett said that US gov can never go bankrupt because it owns the printing press.
What I think is far more interesting is what happens internally: the US is a powder keg of economic and racial inequality and our leaders are either throwing lit matches at it or gently disapproving of those doing the throwing. If COVID cases and deaths keep increasing I can't see how we continue without structural changes.
Hyperinflation is one way to throw more fuel on the dire that is American society right now. And Trump said the quiet part out loud during his campaign[1] that we don't have to repay the whole debt (normally something that the most powerful people in a country don't say in public).
Neither of these ideas works in practice without significant tradeoffs. The US dollar only keeps its value because people around the world have faith it is worth something. A spike in inflation or a debt default would have investors scramble to move their assets elsewhere.
[1] https://www.npr.org/2016/05/09/477350889/donald-trumps-messy...
https://www.federalreserve.gov/monetarypolicy/bst_recenttren...
The only reason store-brand sliced white bread isn't $10 right now is that money only went to investors and businesses.