Running out of people willing to lend us money is the ultimate risk. The more we borrow the sooner that happens.

You mean the more we don’t pay back? Carrying debt generally increases credit rating.

Only up to a point, try borrowing say 50 million dollars while making 50k. Before lending money people look at your existing debt load to determine if your likely to pay it back. The same thing happens to countries, though more smoothly as they first require higher interest rates.

Governments are not households. Using this metaphor only causes more misunderstandings.

Except Greece for example recently hit it’s borrowing limit with spiraling interest rates. If it could have borrowed unlimited money at zero interest nothing bad would have happened, it could have paid debts with new loans.