The government borrows money (creates new debt by issuing Treasury bills) to pay off existing debt (maturing Treasuries). It certainly does retire existing debts, it just makes new ones even faster.
Okay. the government “replaces” existing debt with new debt PLUS some.
When I refinance a house I use the proceeds from the second loan to pay off the first loan. And I only make payments on the new loan. The first loan is “retired”.
If I did it the way the government does it I’d take out a mortgage twice the amount of the existing mortgage then say I paid off the first mortgage. Now I’d owe twice as much on the house as I did. But that first mortgage was paid off! Yippee!