https://en.wikipedia.org/wiki/American_Dream
The discovery of gold in California in 1849 brought in a hundred thousand men looking for their fortune overnight—and a few did find it. Thus was born the California Dream of instant success. Historian H. W. Brands noted that in the years after the Gold Rush, the California Dream spread across the nation:
The old American Dream ... was the dream of the Puritans, of Benjamin Franklin's "Poor Richard"... of men and women content to accumulate their modest fortunes a little at a time, year by year by year. The new dream was the dream of instant wealth, won in a twinkling by audacity and good luck. [This] golden dream ... became a prominent part of the American psyche only after Sutter's Mill.[12]