The difference is that in our world people do express desire to cooperate, also on a global scale, but reaching consensus seems like an intractable or practically unsolvable problem. Everybody knows that cooperating lies in their own self interest, but what does it effectively mean to cooperate?
It begins at different levels. For example, before we even begin to see disagreement on how to do the the things we want, we already have no consensus on what to do in the first place.
Good thing that old thought experiment isn't based on empirical evidence from the real world as the first woman to win a Nobel Prize in economics showed us [1]. In both cases, it's in all participants interest as the GP said but there are some further conditions that Ostram outlined. It turns out in the real world, those conditions are met more often than not and can clearly met in this case.