Capitalist nation-states have no ability to solve collective action problems because they're explicitly designed to be unable to. Nation-states exist to make their own nation rich and powerful, which requires them to treat all other nation-states as adversaries. When a problem comes up that would require the barest-minimum level of trust between adversaries just to avoid mutually disastrous outcomes, we end up with things like the Cold War or climate change. Nation-states don't solve the really big, hard problems collaboratively. They use them as geopolitical contests.

They can cut deals with each other, they can respond to pressure campaigns with PR, but they'll never be able to do anything other than the shabbiest, most selfish bullshit in response to one of the greatest challenges in human history. So far, it's all they've done.