In Paul Johnson's History of the Jews he makes a very interesting and possibly original observation.
Johnson suggests that major population shifts, by themselves, can generate an increased output of commerce.
That has certainly been the case throughout history in which European rulers and Middle Eastern potentates have invited Jews to settle and been rewarded with significant increases in commerce and royal treasuries.
There was a rapid change in population due to the advances of Genghis Khan and his son across most of Asia and I see no productive increases. The same was true for many other invaders from Napoleon to Hitler. They drove hordes of people in front of them to no apparent economic benefit.
In fact, like the Spanish, in 1492, the Portuguese a few years later and East Europeans in the mid-20th century, these nations were commercially emiserated.
Certainly the most recent and powerful evidence that population movement is not necessarily commercially productive is the mass exodus of Arabs from the old state of Palestine. They have brought misery wherever they go. I should also mention the Rom people who have moved all over Europe without any known economic benefit to anyone.
Johnson has a brilliant and insightful idea. It seems only relevant to Jews and possibly to the settlers in the vast American heartland.