There has been a long-standing debate in biology about whether it makes sense to talk about group selection. The orthodox theory is that selection and evolution work at the level of individuals only. A minority, including David Sloan Wilson, one of the strongest proponents of group selection, argue that it makes perfect sense to talk about group selection. Successful countries, religions, cultures, etc. succeed where less successful ones fail. 

The results we talked about with Generous TFT (or other generous strategies) offer an argument in favor of group selection. Individual Generous strategies do not thrive on their own, but populations of Generous individuals overtake populations of selfish ones. 

Here is a nice discussion by Wilson. Be sure at least to read about Muir's chicken experiment towards the start of the article. 

Before you can say that, you have to clarify what you mean by "Armenians have survived because they have never resorted to tribalism. Individualism has always been at the core of the Armenian culture. Thus, we have survived first as individual human beings, and only then as Armenians."

When do they put survival as Armenians over survival as individuals? To put it another way, if Armenian A has less wealth than Armenian B under what circumstances would A steal from B? If the answer is "never" that means that tribalism as you call it trumps individualism. If the answer is "always" that means that the group is unlikely to survive very long because they will all kill each other, as in the chicken experiment. 

In fact if individualism is the highest good why would anyone even talk about the survival of the group as such? No one would care about a group identity, only about themselves as individuals.

Here is something that I think might have been a confounding element in Muir's chicken study (though I haven't read the original paper - I'm basing this on a discussion between Wilson and Muir):

The high-egg producers were taken out of their groups to make a new group, while the control group remained undisturbed.

Is it possible that the high producers weren't aggressive to begin with, but became so because of the stress from being removed from their social group? If so, their chicks were socialized by stressed hens in violent environment - which could account for their behavior. 

The idea of group selection appeals to me politically - any scientific result that disproves Ayn Rand is music to my ears - but I think it is possible that in this study the violence was an artifact - a culture that arose from humans sticking a bunch of stressed out chickens in one coop.