Wealth does "trickle down", when the wealthy are encouraged to spend.
Democrats discourage spending by taxing the wealthy.
Republicans encourage spending by reducing taxes.
Did you even read the damn study? This covered 100+ countries, and you're full of shit, this refers to the world, not just partisan America, and taxes were cut for the rich, decades ago, and yet, it's not trickling down, at all, yeah, yeah, we know how republicans want to cut taxes for the rich, it's a ******* disaster, productivity is at all time highs, incomes are shrinking, wages are stagnant, and the rich just keep getting richer. What do they need, more tax cuts? LOL.