The rational move, the actually selfish move if you follow it through, is coordination. The rational move is figuring out how everyone wins, because that's the only way anyone wins long-term. Ruthlessness works for short-term extraction. Compassion works for the long game.
This truth doesn't require people to become saints. It requires people to update their strategy. Belief is the refusal to collapse probability to zero. The difference between zero probability and non-zero probability is not a matter of degree. It is a difference in kind.
When you see that, the calculation changes. You stop betting on collapse. You stop preparing for loss. You start building for a future where we figure it out together. And that shift in belief, that shift in what you think is possible, is the thing that makes it become possible.