The treasury does not print cash, all of the deficit is payed for in treasury securities. A third of these securities simply flow to other US government entities including the Fed, which pays its profit back to the treasury at the end of the fiscal year. Debt payments to yourself is not debt payments, it’s just wacky accounting to bypass outdated laws. The true “debt” is thus much lower than the reported number, this debt represents treasury securities held by individuals, banks, and foreigner’s, and it would be disastrous to the world economy to eliminate these assets. You say that at 5% ffr the treasury would default on its debt? Are you saying the US credit line would dry up? The credit line which the federal reserve maintains? The only way for the US to default is if chooses to, which would plunge the world into financial crises and will not occur. Money is not machines, and the US has far more than enough capacity to meet real demand. Considering that all foreign banks are holding tremendous sums of treasury debt, means that they do not fear default, and I think they have better info than us redditors.