Scenario 1: It will be nothingburger right until the time it isn't. US can't default on its debt - so massive inflation and money printing until everything is rebalanced.

Scenario 2: AI and robotics deliver growth on par with semiconductors and internet. Couple of decades of the economy growing faster than the debt will put it in manageable ratio.

USA is really rich in resources, extremely well defended by geography, so I guess they will make do even in the worst scenarios.