I was talking about literal gold rushes. I find them quite fascinating and have read a few books on their history. Once the actual "gold rush" starts, very few miners coming from afar get rich. Those who do typically either (a) are supplying the miners, (b) innovate in some way, e.g. buying small stakes in many claims and reselling shares to speculators.

The people who make the most money are parasites and could have done that anywhere. The yields are just bigger in the gold rush ecosystem. The ones who actually struck it rich were the grizzled prospector types who happened to be in the right place at the right time.. but not because they were lucky. You make your own luck as the saying goes.