It's a mistake to think of it as based on ideas or economic theory, debunked or otherwise. "Trickle-down-economy" is a marketing term, intended for rhetoric.
Tax policies, and other corporate friendly loophole machines are all about detail. At the detail level, both rhetorical slogans and technical theories have no meaning. Any given legislation can only be understood as accounting spreadsheets and scenario plans. There's no way to "narrate" it.
One side thinks in terms of objects that have independent moral implications, like shell companies. The other thinks in terms of objects that are a collection of accounting details, like pass-through entities.
There's an old business adage: "you name the price, I'll name the terms." In a startup context, that could mean investing in a company at valuation X, but with terms (eg liquidations preferences, performance goals, etc.) that make a mockery of X as a valuation. Many a vein founder has been scheisted this way. Proudly boasting their impressive, $X valuation and paper-wealth, while giving away the farm.
In corporate law and tax codes, one side has been consistently been winning this game.