
Important in automation is work done by a machine, enhancing or replacing labor. Machines require energy, both for running, and for construction and processing of the material in their constituent parts. Energy was present in the English Midlands in the form of coal. By burning this coal in a glorius steam engine, of which models were improved on from the 1600s and onwards, wonders arose.
Perhaps this book on economic growth would be of interest on the importance of energy for economic growth: The Economic Growth Engine, by Ayres and Warr. Excerpt at https://books.google.no/books/about/The_Economic_Growth_Engi...
Describes the economy in thermodynamic terms, as a materials processing machine, in contrast with neoclassical models of abstract "factors of production". Does a deep dive on examining what technological progress is and how it happens. I don't agree with everything in it but the perspective is unique and highly thought provoking.
https://www.amazon.com/Economic-Growth-Engine-Prosperity-Int...
On the question of whether there's a singular trick that's exploited, I'm not aware of anything in Tainter's writing that suggests this at all. There is the concept of Leibig's Law of the Minimum -- the idea that for any system (Leibig is speaking of ecosystems or populations) there's some one factor which imposes a constraint on the system. In that regard, you could could likely look at a single technology which is the operative constraint. But if you're looking at a complex system with multiple modes of failure, you'd be arguing precisely the opposite: that there are multiple technological tricks which aren't presently binding constraints but which, if any one of them failed, would rapidly become one.
There's no basis that the trick need be unique. I'd argue that they're anything but. Basic modalities include agriculture, construction, fire, transport, arms or weapons, and control over hygiene factors.
The United States' trick was in large part massive overwhelming self-sufficiency in resources, most especially energy.
See Vaclav Smil, Energy in World History, Manfred Weissenbacher, Sources of Power: How energy forges human history, or Robert Ayres, The Economic Growth Engine: How energy and work drive material prosperity.
http://www.worldcat.org/title/energy-in-world-history/oclc/3...
http://www.worldcat.org/title/sources-of-power-how-energy-fo...
http://www.worldcat.org/title/economic-growth-engine-how-ene...
