It's noted in the links, Gordon's research paper in particular goes back centuries and covers the main Industrial Revolutions (3). The links in the OP are the meat of the discussion, not the intro I wrote.
edit--you can't eat an iPad.
Hazir's correct about 'income growth' since the 70s. That era had only one IR (technology/information), and was the beginning of higher income inequality, shedding jobs, restructuring labor, etc. Other theories assume the financial engineering, monetizing mortgage debt, and the housing bubbles were
reactions to globalization and slow domestic growth. More short term 'profits' in asset switching, than real sustainable growth, with a growing middle class. That's part of the Big Picture, too.
As for policy....'austerity' that strips funding from education, health, or infrastructure aren't recipes for growth. It's hard to pin down Romney's proposals (because he flips around so much, and doesn't give specifics) but I'm pretty sure Ryan's budget
assumes 4% growth in GDP in his math. That's part of the theory that tax cuts create jobs and grow an economy, and Trickle Down. Well, the last decade or two rather busts that theory. The wealthy have recovered and corporate profits are high, but their trillions in cash aren't putting folks to work. And the middle class is still stuck in the doldrums.