There's quite a lot of evidence that prehistoric (early, stone-age, etc) humans normally had more than sufficient food. Hunter gatherers had vast and unpolluted territories from which to take animals, fish, edible plants. A very quick Google brought up one brief account, for those who like links, but I am a pretty well read enthusiast regarding prehistory, and the notion of half-starved savages is, according to most evidence, just not true. Early humans weren't weak or stupid. Greed in early societies would not likely have made one more likely to survive - altruistic people may have been more likely to attract mates, in fact, since gifts are always appreciated, so the whole premise of "An insatiable drive for wealth is hardwired into our brains by evolution" is most unlikely.
I see Harold Gilliam is an award winning environmental journalist (Wikipedia), but I see no evidence that he knows much about prehistoric humans or evolution.

http://www.primitivism.com/health-civilization.htm