No, it is predicated on the assumption that $500 at time t is worth $600 at time t+1.
In other words, Fred can bring new wealth into the system, yes. If he defaults, then Ginger learns that a key assumption of her loan---that the wealth of the Fred/Ginger system would increase at time t+1---was wrong. Which is exactly my point: that our system of finance relies on the implicit assumption that the economy will grow.