That's never the preferred answer. That's the trivially achievable answer, given the sheer bloody-mindedness of the body politic, and the difficulty in really, truly convincing even a small portion of the population of existential risk when they haven't already lost family members to said risk. It is literally the least we can do, while still doing something.

The fact is, I can't fight global warming with my own actions. Collective actions are required, and they need to be fairly substantial sacrifices on the part of society. Coordination problems on a national/global scale are just not a thing we're good at solving without force of arms.

Enterprises that cost trillions of dollars are a thing we have the luxury of affording; All we would need to do is get supermajority agreement on the subject.

Nope, what you're forgetting is that most people are in no position to advocate for such extreme measures and have any chance of success. Politics is the art of the possible. Advocating for things that have some chance of happening makes sense.