Set,
If you stand back far enough to see any given society as a whole you will notice that the behavior of any society of intelligent beings is formed by the same imperatives as any other grouping of animals only more so.
This I don't think it is metaphysical at all. Statistically one can predict with some assurance the behavior of the group without necessarily knowing what each individual will do.
Consider world Jewery. It has remained as a society despite being broken up as the various Diasporas took effect. And as long as any portions of the society remain as a viable breeding population the "society" will be relatively intact.
Consider a sponge (or most of them anyway) They are actually a colony of similar animals with somewhat different functions and as long as it is not broken up to the point of being unable to reproduce there will always be sponges. The "society" will be relatively intact.
Since history has been observing the Jews for some four thousand years there is some reason to believe that a given change in environment will cause a response similar to one that has already happened to the society in the past. The Egyptian Exile, The Babylonian Dispersal, and the Nazi "final solution" will all provide clues as to the behavior of Jewish society as a whole.
So therefore by observing the Jews I think it possible to extrapolate their experiences to some other more or less exclusive societies. The Anabaptists and Shakers come immediately to mind but I am certain a historian could come up with many more examples.
I beg to differ also on this point. I do think Christian society acts that way, as much as any other. That is in a manner necessary to insure its survival.
It must act that way if it is to survive. That's how it works, the protestations of priests and philosophers and moralizers are meaningless when confronted with facts.
"But the evolution of society is controlled by intelligence"
I differ again. Intelligence is simply an asset in the battle for survival. Of little more importance than the neck of a giraffe or the four stomachs of a cow.
"Doesn't monogamy or even polygamy remove competition"
No it doesn't. It intensifies it with respect to the individual but it is beneficial with respect to the society. Anyway most modern societies use war to remove enough individuals to maintain whatever equilibrium that it finds satisfactory. Doesn't matter much how a soldier is conceived. A forest tree is self pruning. An oak tree must kill literally thousands of it's descendents. An amoeba must kill many other amoebae or starve itself.There are only so many rocks for a sponge to live on.
The human animal is not much different. When viewed as individual societies there is no real difference. I won't even mention that monogamy in humans is honored more in the breach than in life.
You or a lion or a horse or a tree or a bacterium stand a far greater danger of being damaged by one of your own species than any other cause. That's the way it is. And that IS how it works
No, I am not a bleak pessimist. I hope that one day we can control our societies well enough to "reach for the stars". I'll admit that the last 50,000 years have not inspired much optimism
Despite my long wind

there are many more aspects of societal competition as a factor in the development of societal groups that still could be mentioned. I won't