I haven't read the book yet but it's in my top ten book list - here's a preview by the author himself.
http://www.pbs.org/thinktank/transcript1105.html
I remember growing up reading 20 year old issues of popular mechanics thinking that back then it's just starting to pay off - and that was 20 years ago. The payoff being that inspiring dream of automatos giving us that much needed option of leisure time to pursue one's path. I'm still waiting...
In one warped sense, i attribute the higher valuations in the US market based on this historically high period of productvity - which isn't going down in anytime soon. Once the US companies starts exploiting green energy in a good way, there'll be another great surge. But that's another story...