In Islam, fully 50% of all marriages are between first cousins. This has been going on about 1400 years. This practice explains a lot about Muslims and Islam. But is also love to see how this would work out in these genomic theories. (Other than explain birth defects, disease, low IQ and insanity)
"'But no man can do wrong who lays his chariot alongside that of a foe, and tries for a spear-thrust. Such was the courage and will of the men of old who stormed walls and laid waste cities.'"
Ahhh, the good old days.
More recent advancements in technology seem to be causing the population to decline.
A fun series on Nat Geo that just aired is The Great Human Race. It had two survivalist actors who assumed the technology of the era and lived off it for five days.
First: use rocks to crack open bones as a scavenger. Then cutting tools. Then spears, then control fire, then domesticating animals, then bronze etc. until arrival in North America where they made cordage and nets and had all the salmon they could ever eat.
Using a rock to smash bones at a kill site was the God moment, around 3 million years ago. We could do something no animal could and became the apex predator and own the planet.