You've kind of hit the nail on the head but it comes across as the nail hitting the hammer rather than the other way round. It is because the climate crisis is not like a horror movie, where everything happens in a matter of hours, that it is getting ignored. Humanity won't sit up and take notice until the world comes crashing round their ears, like some epic apocalypse movie. The whole story has to run in under 120 minutes to keep audience's attention. Someone screaming "We are all going to die" followed by some hero claiming he knows how to save the world, isn't going to be enough. There has to be danger and spectacle and guns blazing (maybe even a car chase) for most people to take notice. Even then you will not be able to get them to take responsibility and be part of the solution. They would rather sit and watch it all happening while guzzling popcorn and drinking slushies.

They are waiting for an action hero (Iron Man?) to come along and save the day so that they don't even have to get out of their seats.

You say that "Humanity is the star of the show" but it is starring as the monster. A greedy ravenous monster, that will stop at nothing to get what it wants and will destroy everything in its path. A monster you can't reason with and too big and powerful to destroy. The climate isn't the monster coming to get us, it is the monster among us.