The debt is always paid off by printing money. That's the way the system iss set up.
Let's say i borrow $100 when it is worth 100 cabbages and there is only 100 dollars in circulation and 100 cabbages.
If I print 100 more but still only have 100 cabbages, then 200 dollars is worth 100 cabbages, of 50 cents per dollar compared to what it was when i borrowed it.
Of course wages rise too. This is called inflation. But the original debt can be paid off by 50 cabbages, not the 100 it was worth when i borrowed it.
Apparently this is too complicated for people to grasp, but it's the way it works.
But, here's the fun part. This is where interest comes in. The interest is the fee payment to the bank for loaning the money. If you buy a house for 100k with a 30 yr mortgage, you will end up paying back 300k. This is why no one WANTS to balance the national debt. If they did that, our entire financial system would collapse. There would be no reason for banks to exist and they would have to take over the old fashioned way, with a military coup.
Did you happen to notice that for the past 9 years, when inflation was held artificially low, to keep the economy from deflating, the credit market has been tight? There was no profit in lending, so banks didn't do it, except to sure bets.
If you don't believe me, i'll put my money where my mouth is. The fed has raised the prime rate twice since nov 2016 and will do it again in a few months (my opinion). That is injecting inflation slowly into the system, which devalues the debt. The credit market will loosen up and banks will start lending again.
Another side effect of all this is even more economic/social stratification. The rich get richer, the poor get poorer, but at least they can find a min wage job, because upswings encourage entrepreneurship, for the rich and the credit worthy.