Well, there is much actual evidence that it really trickles down.
In the Real World of Work and Wages, Trickle-Down Theories Don’t Hold Up
By ROBERT H. FRANK
If economic theory is unkind to trickle-down proponents, the lessons of experience are downright brutal. If lower real wages induce people to work shorter hours, then the opposite should be true when real wages increase. According to trickle-down theory, then, the cumulative effect of the last century’s sharp rise in real wages should have been a significant increase in hours worked. In fact, however, the workweek is much shorter now than in 1900.
Trickle-down theory also predicts shorter workweeks in countries with lower real after-tax pay rates. Yet here, too, the numbers tell a different story. For example, even though chief executives in Japan earn less than one-fifth what their American counterparts do and face substantially higher marginal tax rates, Japanese executives do not log shorter hours.
Trickle-down theory also predicts a positive correlation between inequality and economic growth, the idea being that income disparities strengthen motivation to get ahead. Yet when researchers track the data within individual countries over time, they find a negative correlation. In the decades immediately after World War II, for example, income inequality was low by historical standards, yet growth rates in most industrial countries were extremely high. In contrast, growth rates have been only about half as large in the years since 1973, a period in which inequality has been steadily rising.
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The trickle-down theorist’s view of the world is nicely captured by a Donald Reilly cartoon depicting two well-fed executives nursing cocktails on a summer afternoon as they lounge on flotation devices in a pool. Pointing to himself, one says angrily to the other, “If those soak-the-rich birds get their way, I can tell you here’s one coolie who’ll stop” working so hard.
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The rich are where the money is. Many top earners would willingly pay higher taxes for public services that promise high value. Yet trickle-down theory, which is supported neither by theory nor evidence, continues to stand in the way. This theory is ripe for abandonment.
In the Real World of Work and Wages, Trickle-Down Theories Don’t Hold Up - New York Times