Hunter-gather societies were tribal ones. If you weren't part of the tribe, you were not taken care of. While nature is very important in determining human happiness, we can't forget the feedback social progress has made. Just as there are genes, which affect our preference, we also have memes (see: Richard Dawkins) and these memes help us evolve our social behavior. It is very simplistic to limit the perspective of social well-being on solely genetic history. 

Secondly, in nature we see hierarchies. Many of our cousin apes form hierarchial groupings, with an alpha. Furthermore, we also observe the concept of property. Cats and Wolves have "territories." The same holds true for primates. One can say that the want to own property is in our nature just as one can say altruism is. However, what is not natural is the entity which we call the state. And to use the state for altruistic purposes (or to enforce property rights) is going against natural order. If we were to adhere strictly to our natural behavior, we'd allow for spontaneous order to take place. As it currently is, we do not follow spontaneous order, but try to consciously structure groups and societies. 

Let me correct my statement. "Technology would never have developed as efficiently without an incentive (reward.)" 

Also, in a world ridden in scarcity (the world pre-capitalism) there is no means to help others. The only way to help others was by helping yourself, by mutually working together with the aim of higher productivity so that scarcity might be reduced. That is how people were and are helped. 

Tribes don't necessarily live with a Hunter Gather life style, so they are not same thing

Our genetic history is the most important limiting factor on Human happiness, we ignore it at our own risk, we would never do this for any other animal species we wanted to preserve in it's happiest state, we are no different

We are talking about humans, so other animal behaviour is best suited to them not us, Human culture has historically been one of mostly equal sharing of resources up until the advent of agriculture when the differences in individual resources and sharing started to vary by magnitudes from the hunter gatherer

As for social development, most people have had little  influence since the advent of agriculture once a few started to control most of the resources, most Humans then lost power in relation to a few resource rich Humans who are the ones that have shaped society from then on to suit their resource gathering activities and control 

Good point, that is why mostly equal sharing of resource is instinctive it us because it was a way to help others that resulting in ultimately helping ourselves, something we have done for almost all of our Human evolution and probably long before  

While more tribes originated after the advent of farming, there existed tribes that found nutrition through hunting and gathering. This is if you define a tribe as a coalition of bands. Regardless, my point stands even more strongly with the concept of bands, which were even less inclusive than tribes. 

With so many genes affecting human behavior, with different environmental initial conditions, it is quite ridiculous to attribute one way of living as "genetically" human, natural, or instinctual. Many genes express multiple phenotypes and can suit different environments. Social structures (memes) are just reflections of our genes. 

For an example of how society can affect our behaviors, 

@ Bolded, You say that as if there have been one people since the mesolithic. It doesn't stand in today's world though. ALL humans in civilizations accumulate wealth and trade to survive. 

Unfortunately, a totally egalitarian distribution of resources doesn't lead to any real productive economic activity, and doesn't reduce scarcity. The formation of markets was a natural progression after the discovery of new niches and resources. Not all people can do everything at the right efficiency, due to natural variation. Consequently, we allow people to pursue the production they are good at, with their motivation being to reduce their own scarcity. By working in ones own self-interest the interactions they have with others also benefit others. If I am good at growing apples, and my friend is good at growing banannas, and we want to trade so that we can maximize our happiness by having whichever number of apples and banannas we desire, we become more productive. 

ok, so all those people once had good ideas on how to improve life for everyone and had the skills to make those ideas reality. but what about now. do a few good ideas in the past really justify an ongoing tremendous cashflow towards a few people who obiously don't have any further good ideas or the skills to make them happen because otherwhise they wouldn't need to wait for an investment? 

Money makes money. It's a simple fact.
The only things the goverment here can do is put a belt at the paychecks of the CEO and other like jobs. But not too tight because you don't have to punish succes in my opinion.

Also I see a lot of poor people complain about this, but actually they don't do shit to improve their situation.

This is a huge problem in the west, but the established parties will do nothing about it and we all know it. Capitalism has fragmented and become dysfunctional due to misguided policies. Replacing it with Communism obviously isn't the solution but there needs to be a middle ground where government has progressive taxing so it can invest where the rich could but refuse to invest. Governments also need to represent their own public rather than corporate executives. Scandinavian countries are excellent examples of countries that show the middle ground, Social Democracy. It's time we all saw it.

I blame the rise in inequality on privatisation and deregulation of the economy from the 1980s onwards. It's allowed the hoarding of wealth and a lack of investment in key aspects of the economy, especially infrastructure (or social housing in the UK).

Also, to the people who blame the poor for being poor. It's the 1% who are holding back the wealth for themselves and thus keep the poor, poor. By keeping pay low and outsorcing jobs to developing countries where possible, the rich effectively force people to work for peanuts by reducing jobs available while they still pocket the profit for themselves. I'm not against profit but if the employer doesn't pay well or invest in something then it's just wrong. Money can do wonderful things but it's worthless if it's left in a bank account doing nothing.

hopefully something will happen with that