Ok, the way it was explained to me was like this:

GM makes 100 cars and loans them out to 10 people on the promise of each paying back 11 cars.
110 cars don't exist because gm didn't create them.
No interest exists, only principal.

9 of the dealers can repay by buying at the bankruptcy sale of the tenth one.
Wash, rinse, repeat.

It is mathematically impossible to pay back the debt with interest.
The fed does not create the interest to be paid back.
Only principal exists.
Only by some loans defaulting can the others add up.

Every dollar in your pocket came from the bankruptcy of some unfortunate family.
Keep working, stop paying.