We humans have a fine nose for fairness, or lack thereof. Even before they learn about fractions in school, children can tell whether or not a pie is equitably divided. So if you're trying to propose a plan that makes things less equitable, you'd better have a convincing story.
Reagan's "A rising tide lifts all boats" was one of those stories. The 1980s rang in an era of rising inequality not seen since the Roaring Twenties.
This is true globally as well: the global version of Reagan's story was that globalisation would lift all boats, including those in developed countries. It did work out that way, but only for selected countries, like South Korea. In general, globalisation has caused the playing field for the accumulators to expand, so that now a handful of people - 26, to be precise - owns literally half the wealth in the world.
What did the rest of the world get out of it?