Whatever that wolf might be, it isn't going to be that the government can't produce more dollars to spend. It always authorizes itself to spend money and it always produces enough of that money to spend.
Governments going into too much debt is a very old problem that has happened hundreds of times before, even in the USA, so we know with high likelihood how it ends: inflation and soft default, not hard default. The timeline is the major unknown.
Inflation is not exactly preferable to hard defaults, although it really depends on who is being defaulted on. Defaulting on pensioners would be pretty awful. Defaulting on foreign-owned bonds would be less awful.
