Exactly. Any breakthroughs in energy efficiency would result in more productivity, increased GDP, increased incomes, etc. All these would drive the cost of oil through the roof. Jevon's Paradox will ensure that oil is going to be expensive proportionally to whatever technological breakthroughs we can come up with. Even if we had a zero point generator, oil demand would shoot through the roof because zero point generators would ignite a building spree unlike anything the world has ever seen. (Including China!) Even if we had free energy, we'd still need all the oil in the world just to build an infrastructure that could make use of free energy. That was a pretty grim realization for me...