You know how scientists announced they got slime molds to solve mazes? I imagine it could be something like that. The slime mold is just looking for food and living its life. What it doesn’t realize is that the food has been put somewhere that will force it to solve certain computational problems along the way.
Now imagine a central scheduler breaking down computational problems into bite-sized chunks and using an immersive storytelling simulator to force a few billion humans to do something similar. I could see it, in theory.