This is important. The relative frequencies mean that observer bias cuts all the harder.

Additionally, it's very difficult to take the winner and back-calculate the particular winning strategy. The pick-axe sellers won in this case. But one story is not statistics.

Finally, it's important to note that the story sounds good and that makes us believe it even more strongly...

(I bet it's even better to be a banker at the time of the gold rush, incidentally.)