Good question. The impact wouldn’t be as limited as first appears-

First, who will take the hit? Somebody is owed the money, contractually, on for a bond security.

Debt is sold off, but not just to the super rich. Keep in mind regular people own government bonds in their 401k accounts.

Essentially, mom & pop are letting the government hold their money, so long as mom & pop get all their money back plus a fee for letting them hold the money (interest). Since it’s the government & the government can tax people, one could assume the government will pay back more & pop plus the interest). If the debt is just cancelled, it doesn’t look well for mom & pop. (Print more money = inflation).

Secondly, a big chunk of US debt is owned by foreign countries. The resulting possible scenarios here are scary.