I don't think most wealthy people swim in their cash like Scrooge McDuck. They invest their cash in public and private companies which often generates plenty of capital 'flow'.
True, but there's more to it. Interest rate is used to slow GDP (and inflation). Using the blood analogy, it's like lowering the blood pressure. Which means people do freeze their investments or put it into things like gold or crypto.
The other end is it gets invested heavily into profit making stuff. Plantations and farms and power plants are great. But not all of this money benefits a society in the long run. There's stuff like garbage and prisons. There's things that require a lot of investment like educating certain minority groups. Tax money is generally more effective for this. Too much is not good though; we need a balance between state and corporations.
