Of course I understand that the money that is put in is invested, but that doesn't mean the problem goes away when the system relies on the "pot" growing at a certain rate.

EDIT:

Mismanagement/poorly built systems are not the same as Ponzi schemes. Unless you think, I don’t know, US Social Security is also a Ponzi scheme?

I'm not implying that it's the same, just that the comparison fits better than you might expect.