Careful, it's not like there are no cultures in between the Neanderthalic hunter gatherer societies, and our totalitarian-agriculture. There have been thousands of cultures that have been tried, practiced, and eventually over-run by our culture today.
You can see that the agriculture we practiced not only provided us with substantial amounts of food (which caused population increase -- it's not that we have any choice over this, the more food you have the more babies you have, that's just how life works.) but it also demanded that our way of living spread. You can't just be happy with a contained amount of totalitarian-agriculture, the population will sky rocket, and you'll need to continually expand, looking for more land to claim as yours to grow more food to sustain your unnaturally high population.
Another thing to consider is that each culture has their own traditions. We started out simply farming, but began to have a need to write things down, we began needing to write things down, to support the auxiliary consequences of having all this extra food. It use to be that you didn't have to store this food, you didn't put it under lock in key, food was available for anyone and everyone whenever you were able to get some. But all of a sudden our new agriculture system needed a place to store all the extra grain, to keep track of it, and to trade it. The result is that our style of life is the most labor intensive (compared to calories consumed) in the world. Just think about this, not only do you need to spend the energy to grow the food, you've got to spend energy to store the food, to transport the food to the market, and to sell the food; on the other side, us non-farmers must go out and get a job, do our work all week long, to earn money, (a completely meaningless substance outside our culture) to buy our food. Compare this to the fox that simply needs to wait around, stalk a bunny rabbit, and pounce on it when he's hungry, our style of life demanded this highly complex system of work and energy to support itself.
Yipes, i've gone off on a tangent, what i meant to get to in that previous paragraph was that traditions vary in each culture, i've explained why we have such the record that we do. It must be understood that there are many cultures out there that never had to spend the time creating a written language, or creating mathematics or inventing crazy technologies to support themselves. This does not mean that alternatives existed; For example a culture who had a predominantly oral history will not be able to be found by us now if everyone of that culture is dead...for obvious reasons.
It's very difficult to gain a perspective on our way of living, as it's the only way we've ever really interpreted the world, since birth. We should be able to realize our strangeness, but compair this task to the task of understanding why some tribal cultures practiced canabalism, or human sacrifice, and it's just as hard. If you tried to imagine a life where the Aztec culture was the hegmony, where human sacrifice was NORMAL, that it brought about good fortune for the crops, or that Maori canabalism was completely normal -- I'll admit it's dificult for me to understand. We can apply this difficulty of understanding to the task of recognizing the bits of our culture that are crazy.
again i've gone on for too long, i'm sure i've lost all but the most dedicated of audiences at this point, thanks for reading thus far. I suppose we could go on to some of the crazy practices of our culutre, but i'll save that for a future post, if someone actually made it through all of the above.