This "bold new theory" is more of a lovely and apt observation of developing worldviews... taking a single (though important) influence into account. However, modern personal and societal research has identified a great many factors beyond energy capture that produce a predictable series of developmental stages along multiple lines. Have a look at the modern work such as Ken Wilber's Integral Theory and Don Beck's Spiral Dynamics for starters.
These pop up routinely. Its Ian Morris' version of Jared Diamond's GUNS, GERMS & STEEL, that posited geography as the major determinant, as did Paul Kennedy in RISE & FALL OF GREAT POWERS, geography/economics. James Scott its the technologies of bureaucracy, like writing. Back in the day it was military technology, Gimbutas and the Aryans coming off the Eurasian plain in their chariots. I find that the archeologist/geographer/anthropologist's area of specialisation tends to yield the magical single-main cause. Prof Morris would not choose military technology, I doubt he can distinguish a sarissa from a doru.
I would have appreciated an explanation for why low inequality is bad, apart from the "everyone agrees it's bad, so it is" argument. It's an interesting and - to me - shocking claim to make. I wish I felt closer to understanding why it should be the case. A psychological analysis of this distaste that "everyone" has for equality would be fascinating, specifically with the people who stand to lose out from inequality. Are *they* really (subconsciously or consciously) championing inequality, and if so, why?
+Those Things It has a bit to do with spending ability of capital. Also note on how he states that with the trend that started in the 1970's the inequality values are teetering on the high end of .35 and it is causing strife (collapsing middle class, which was essential for market lubrication on real assets). So if you want to see how this really is useful the rich really need to spend their capital, which was the idea of top down economics, of coarse this is not happening that way which means there are bad 'values' involved.
+ndyt I think the argument he is making is that how you extract energy is basicaly how you survive. That is survival, and comfort, is achieved by use of energy which was in some way extracted.