The article mentions several times that the Icelandic form of government lasted longer than the US - if anything I see that as a negative indicator, given how little actual progress occurred during that time. Compare the impact the US system of government has had with the impact the Icelandic form cited in this article had. The indigenous populations of North America and Australia have been around for thousands of years as well, with their "chieftain" systems of government, and similarly they just stagnated.