Got a sprain? Call a doctor. Leaking pipe? Call a plumber. Doesn't seem nebulous at all. Conversely, speculation and greed ruining the world? Call on the populace to bail them out. Speculation doesn't build or fix physical stuff.
>You mean some sort of planned economy? Those have not worked well historically.
Because historically it has been done on inferior computers. Whereas now we have the computing power to calculate the economy n-times over. Dr. Paul Cockshott on Cybersocialism: https://www.youtube.com/watch?v=LtlZys7QOO4. That being said, I'm sceptical as well; the video leaves many things unanswered which he expands on in his books that I have yet to read. However, I welcome any ideas on how to detach humans from having to deal with money, so we can collectively pursue more lofty goals, beyond profit.