In humans the evolutionary pressure for evolving a higher intelligence is mostly driven by war, and war is driven by the emotion of vanity which drives envy. Although not always, the best and brightest usually survive war disproportionately. WWII drove a measurable intelligence bump in the surviving population.
I see your thought process in this, but it's been proven research that Jews have increased intelligence derived over two thousand years of survival in other nations by using their wits. Everywhere they went, they survived by evolving higher intelligence. The survivors from WWII retained this genetic gift.