First, I do not think Steven Pressfield is a "anti-west leftwinger" or even sounds like one. True he is dealing with broad, sweeping impressions born of his research in this area.
The pattern in the mid-east is for a King or Tyrant to overwhelm the tribalism of the peoples which constitute his domain. When that king is gone, the feuding factions reemerge. And I think we see that now in Iraq.
The tribe, it seems, is alway at war. And its sense of justice seems unlike that of the Hebrew or Christian eye-for-eye varity (a good thing--it introduced equity into law).
I'm not convinced that efforts to democratize will necessarily fail. Can the tap roots which feed tribalism be cut? Real Islam will continue to keep these people in this bondage, in my estimation. Western cultural influence might produce another Turkey. However, the greatest threat to tribalsm is Christianity.