I run into these firm believers of this "theory" all the time. And if I bring up, say, restoring taxes to the historic burden the wealthy had between 1945-1981, it always gets shot down as a "bad idea". Basically the wealthy, economically hold this country hostage, they will leave, if they pay higher taxes, and then that's bad for the country because the wealth holders just leave with all the country's money rather than pay taxes.

The idea is when the wealthy, get very wealthy, their "pots boil over". A "rising tide lifts all boats". The whole premise of Trickle Down Economics, is in order for the economic theory to be successful, the wealth has to trickle down. If the wealth consolidates, then it's easily argued, that the economic theory is a failure, and the measures to implement should have never been made public policy in the first place.

According to Supply-Side supporters, a wealthy person/business owners "motivation to work" is irrevocably tied to how much income they make. So if we, essentially, give this economic class, more money, they will be even more motivated to work, and that helps everybody. On the opposite of the economic spectrum, the poor, if they get "help" with basic living needs, their motivation to work goes down.

So in essence, the poor "have too much" and the wealthy "don't have enough".
But I don't know I look at the results. In 1960's Baby Boomers were getting Middle Class jobs out of high school, buying brand new cars, houses, by the 70's and 80's starting families. If you were born in the 40's, you stood a 90% chance to make more money and have a better standard of living than your parents.

The Millenials who have grown up with Supply-Side economics in place for decades, our college graduates have a combined debt of $1.3 trillion. Workers incomes, in terms of purchasing power, have remained stagnant for about 30 years. If you were born in the 80's, you stood a 50% chance to make more money and have a higher standard of living than your parents. Millennials well into their 30's, still live with their parents, while the Baby boomers were buying houses.

Meanwhile the wealthiest 1%, 0.1%, and 0.01% have been economically doing great. But according to Supply-side supporters, "not good enough". Congress has passed a bill, that wants to remove health coverage for over 20 million lower income Americans, to implement another tax cut on the wealthy, because they truly believe this is the best way to improve the American economy, and the ordinary American's life.

I don't really understand this theory, and why it's so overwhelmingly popular in America. It sort of boggles my mind, after a tax cut is passed, and the ordinary American's life hasn't improved drastically, the answer always seems to be to double down further on the economic theory, and pass even more tax cuts on the wealthiest Americans. I guess my question is "When will the wealthy, be wealthy enough, for Trickle Down Economics to work, and improve the ordinary American's life?"
Clearly 400:1 CEO to worker pay ratios, is still not enough, judging by the economic state of say Millennials, vs Baby boomers at this time in each others lives.