Guns, Germs, and Steel is a famously awful book.

Anyway, another lens to look at kinship relationships through is as a resilience strategy to volatile conditions. Any given stress (drought, job losses, etc) are unlikely to affect everyone equally, so the network functions as a safety net under many conditions.

Venture capital applies a similar strategy in the other direction if you squint a bit. It's impossible to predict who will succeed a priori, so the capital is spread to many different bets simultaneously in the hope that the successes outweigh the failures over time. Many of the "rituals" in the VC ecosystem (ghost hiring, puffery, fad chasing, etc) aren't particularly useful for any individual company's success, but I don't think many people here on HN are going to argue it's not economically effective as a whole.