If you center the Map over America you'll see the center of economic activity being America. If you center it over Asia, it'll be Asia.
Therefore this map does not contain much more information than "Greenwich lies in the middle".
Isn't that also true of the original map, though?
It's not at all clear to me that your visualization is an improvement on the original. The center has moved from Scandinavia to Spain, and I can see why Scandinavia wasn't a great center, but I don't see why Spain is better. Meanwhile, your visualization depends on the projection used, which seems highly nonintuitive.
(If you go from the USA to China by the shortest distance, you go near the north pole. Calling the north pole the average of the two places may seem strange, but calling any other place the average is even stranger.)
There are better ways to represent the information presented. A 3D map would put economic activity somewhere in the middle of the earth, but you would eliminate the "starting center" bias.
If that is still less than optimal, maybe try the south pole ?
Seems to me it might correct the bias seen here.
From the article:
"There was one thing which bothered me, and I hope it bothers you too, the points from the 20th century are all positioned in or above Scandinavia which seems unlikely to be the center of anything in the world. You can find the reason for that in the caption on the McKinsey webpage. Their report looks at the Earth as a sphere and finds the economic center of gravity which falls somewhere inside the sphere. To plot it on the map, they take a radius through the center of gravity and intersect it with the surface."