brynndragon | Thoughts that keep me awake at night

Supply-side economics includes the notion that money trickles down from the rich to everyone else. Has anyone ever done a study to see if this is actually the case? I'm thinking a retrospective study of what the rich do with their money and following where it goes from there (surveys should be sufficient for at least a first-order approximation). It's basic science: a theory gives you testable hypotheses which you need to test in order to demonstrate the validity of (at least portions of) the theory. Did anyone do the research?