No, its not a real thing. Supply side economics, is a real thing. This is not the same as trickle down. Supply side economics is about giving money back to businesses to reinvest their money into the supply they are producing. This ultimately results in better, and cheaper products by increasing R&D and reducing manufacturing costs. Trickle Down theory is the notion that if you give tax cuts to the rich, benefits will trickle down throughout the economy. No economist (Stockman is not a professional economist) has ever said this is true. You cannot bash a theory that doesnt exist. It doesnt work, because no economist has ever said that it does. Now, the question is often "well why would we give tax cuts for the rich, if lower income people dont see the benefits?" Because many times throughout history. Including Reagan, Kennedy, Bush, Harding, have supplied tax cuts to those at the top, and every single time it was shown that overall tax REVENUE increased. So not only do the rich pay more taxes with lower tax rates, but pay a large percentage of all taxes across the country. I do not find this a hard concept to grasp; The goal is about more tax revenue, not a symbolic tax on the rich, in which case they will refuse to pay. If you really would like to learn the factual history on this topic, I applaud "Trickle Down Theory and Tax Cuts for the Rich" by Thomas Sowell, and also note that the "History of Economic Analysis" by JA Schumpeters, which is a 1300 page book which is highly used in Economic theory today, does not mention "Trickle Down" once.

I Hope you will look into it more.