[fourtrees]

I like this answer, and Krause's on my reading list now. I have to speculate that the development of the organizational/institutional capabilities to produce bronze on a large scale (especially the need for reliable long-distance trade networks needed to acquire tin (or pre-made bronze) en masse), and not just the effectiveness of the material as an arm (and the feedback between these two factors), was a very important change. 'Suddenly', you have a whole part of society whose livelihoods are dependent on the bronze industry and who would seemingly be willing to fight to keep their potentate(s) in power if it meant keeping their trade afloat (were the original nobles just the members of the local bronze 'guild'?). And of course an even larger segment of the population willing to go along with it for their own safety.