Why is the AI conversation all doom and job loss, and not the golden age it could bring?

Every AI headline seems to be about mass unemployment, runaway superintelligence, or the end of work as we know it. What I don't get is why the big AI companies aren't loudly and publicly committing to projects that would benefit all of humanity: solving the energy crisis, curing cancer, ending food and water shortages, accelerating clean materials science. I know there are bits and pieces out there (AlphaFold, some drug discovery partnerships), but nothing on the scale of a moonshot with public goals, timelines, and accountability. With AI and robotics advancing this fast, it feels like we could be on the brink of a golden age for humanity. Yet the dominant narrative is fear. So I'm curious: Is it a business decision (no clear profit, too much liability if they fail)? Is the tech not actually capable of this yet? Or are these efforts happening and just not getting media attention? Would love to hear from people in the industry or anyone who's thought about this.