A ponzi scheme can turn into a roughly zero sum game if there isn't a rush but instead stable behavior over hundreds of years. Which is exactly what you describ

A ponzi scheme can turn into a roughly zero sum game if there isn't a rush but instead stable behavior over hundreds of years. Which is exactly what you describe with gold. Plus, gold actually does have some industrial uses so its value is actually somewhat greater than zero even if people one day woke up and didn't think it looked good for jewelry :P