I think the claim that the entire contents of ArtStation will lead to working technology that fixes climate change is the bolder claim

That's fair, and why I didn't make that claim. What I said was, claiming the opposite is also bold.

there would be some evidence for it that the corporations who want copyright to be disapplied to artists would be able to produce

I don't think it's in the corporation's best interest to solve climate change, though. At least, not in the near term. Their interests are always self-serving. But that doesn't mean the technology they produce going forward isn't our best shot at survival.

And if we're saying that getting rid of copyright protections will save the planet

Which we're not....

then perhaps Disney should give up theirs as well

Ok. Fine with me.

we're expecting humans to be obliterated by AI but are not expecting the rich and powerful to make any sacrifices at all

Eh, so far in this discussion we had not agreed on the former. Maybe you meant "if we assume...why are we not..."? And I would say, we don't need AI to kill us all for me to agree that the rich and powerful should be forced to contribute a fair share to society by society.

And art is part of who we are as a species, and has been for hundreds of thousands of years. Replacing artists with AI...

Correct me if I'm wrong, but I think you're implying that what AI produces is not art. If so, then I don't think there's any risk of AI replacing art. If art is important to humans, then we will still create it and appreciate it. It's like when humans invented fast food: if it's not giving us the nutrients we need, we won't be able to survive off of it regardless of how prevalent it becomes.

but what would we even be saving humanity for at that point? So that everybody can slave away in insecure, meaningless work so the few can hoard everything for themselves?

This is one of those loaded "what is my purpose in life" questions. There's no reason to save humanity at all. There's no reason we exist to begin with. The cynical "we're a bunch of monkeys fighting for resources on a forgotten ball flying through emptiness" take could have been made at any point in human history, we didn't need AI to take over.

the Star Trek utopia where AI does all the work and humans can pursue self-enrichment is not an option on the table.

Strong claim.

The tech bros just want you to think it is.

Agree.

I feel like you are prone to false dichotomies. Just thought I'd point it out.