The chart is flawed -- it doesn't contain numbers predating the Industrial Revolution, when many of the agricultural workers who lived off the land tended to be much happier than the overworked, depressed populations of today. What's the point of "productivity" if you don't have the free time to enjoy the fruits of your labor? Our current system is designed to benefit the people at the top, regardless of how much the exploited lower and middle class workers are paid.