That debate does not change the clear correlation (at least in the 20th Century) between economies that tend to waste their surplus energy on “frivolous concerns” and economies that prospered.

You have the do a lot of work to convince me that the cause-effect relationship goes in this direction. IMO it is self-evident it is exactly the opposite - economies that "prosper" create enough surplus of energy and other resources made available for the people to "waste" the way they like.

I'll bring it even further - discretionary spending is one of the main reasons people are motivated to work harder, and to embrace the economic growth idea. If I earn $1000 per month, but I spend $990 on essentials and only $10 for myself I could hardly be satisfied with my life. I will try to find a way to earn more.

You mentioned the market vs command economy. The main difference between the two is that in a command economy (at least in the socialist version), the essentials - food, housing, education, healthcare etc. are either free or dirt cheap. What you earn is basically for non-essential consumption, and here is where the command economy failed. Because of its nature it did not follow and could not provide what people wanted... and the people simply wanted the freedom and conveniences of western lifestyle. The surplus energy was still there but it was routed inefficiently - to the military, to the government beurocracy or to the huge inefficient industrial complex.

The bottom line of all of this is that you are right - the surplus energy is essential on a societal level. With falling surpluses we would simply have to cut back on non-essentials and accept lower living standard... Personally I won't miss SUVs and RVs, but will hate to see things like air travel go.