>Because unlike in a Ponzi scheme, the US government can simply choose to create more money,

It sure can, but this doesn't go far enough.

The US Govt' can only choose to "print money". It cannot choose otherwise. This is because fractional reserve banking allows financial institutions to lend out the same $1 multiple times.

The result of collecting $1 and lending 6 people that $1 with an expected total payment of $2 per debtor results in $1 causing $13 in the economy.