I also agree it's simple game theory, but ignoring the HN audience for a moment you're probably assuming that the non-zero sum situation will still continue to hold at a society-wide scale for large parts of the world (at least for the "former" Western world).

The present covid crisis has proven that to be false, what with countries/states members of the same political union (the EU, different US States) fighting for limited medical resources in the early stages of the pandemic. We'll probably end up in similar scenarios if and when the climate crisis will worsen, reducing the availability for resources for many of us.