'trickle down' implies a watershed, where water/wealth collects in small tributaries that come together to form a main River where wealth/water is most concentrated.

Actual trickle down economics is trickle up economics, so no shit it doesn't work. Let's just dump a bunch of water here at the mouth of the Amazon and watch it flow up into the Andes.

You didn't answer the question.

Into investment assets that get swapped amongst the wealthy ad-infinitum, and generate enough capital on their own to feed the poor.

The 20/80 rule applies in all aspects of life. Like 20% of the soccer players account for 80% of the goals. So why wouldn't we expect it to apply to money as well? This is like a law of gravity. You can attempt to fight against it artificially but eventually it will come crashing down