If we do look at this from an energy spending point of view.. this robot/AI revolution is gonna have a few interesting twists and turns along the way. One has to remember, the evolution of life has been a constant "economic" struggle for limited resources, with energy being the most limiting factor. Right now our economic development is largely based on a temporary liberation from that. However, that won't last, and energy-wise, life is far more energy-efficient than machines for most tasks[1] (I'm not entirely sure how this translates to robotics and computers, but for now I doubt they win). Energy spending also scales sub-linearly for living things[2], and I'm not sure if that holds true for machines.
[0] http://en.wikipedia.org/wiki/Embodied_energy
[1] http://www.lowtechmagazine.com/2014/03/how-sustainable-is-di...
[2] http://peakenergy.blogspot.se/2011/07/geoffrey-b-west-why-ci...