the annual service on that debt is now more than we spend on Defense.

Been saying this since I arrived on this site 5yrs ago. But neither side wants to fix the problem, one just raise taxes, the other stop spending.
Neither will happen.

US just raised most revenue in its history, US just spent more than it ever had due to mandatory spending.

Never heard of this ridiculous premise framing it as 0 to a 40 trillion though.
Must be that Danforth math at work. The US already owed 4-6trillion.

The US never stopped selling treasuries, despite the supposed "surplus."

Boomers always thinking its everyone else's fault. Boomers it's you, and only you, the spending spree started under you and hasn't stopped under you.