An Interesting Question

Prof De Long plays with some numbers and asks a very interesting question:
"Thus the key question in understanding the economies of long-long ago. Were they people with
motivations like us living in economies that worked more-or-less as ours does, and was the glacial pace of growth and the Malthusian structure the result of the disabilities they labored under? Or was there something very different—and from our perspective very wrong—with the stuff of the economic mechanism itself?"
http://www.j-bradford-delong.net/2008_pdf/20080120_longestrungrowth.pdf