If we don't pay the national debt, the US economy would suffer enormously. Eventually people would lose trust in the US dollar itself causing hyperinflation which leads to the worst disasters in modern history.
That won't happen unless idiots run the Treasury because it's easily rolled over into new bond issues. The worst of the lies are the ones justifying needlessly painful austerity that get trotted out every couple of months equating sovereign debt with household debt. And a little bit more (not hyper) inflation instead of this disinflation we're stuck in would be very helpful to debtors.
The point is that in aggregate the entire generation probably both owns and owes the same debt. Redistribution is clearly happening between groups and country but the entire pool sums up to near zero