One of the weird things about trickle down economics is that the rich's favorite past time is earning more than they spend. Basically the entire thing is built around the idea that dumping money into a portion of the economy that doesn't have to pay taxes is good while ignoring that this money was created through debt which eventually is converted to government debt through various means. When the debt burden grows, tax revenue has to go up as well but you are sending all the money into a no tax black hole meaning the tax revenue vs debt payment ratio gets out of whack.

How is this supposed to work again?

I'd consider "Trickle up" anything that creates full employment. If employees are earning more money they pay more taxes. It kind of does work precisely because the tax burden is so high.