I see a big theoretical and practical problem with Figure 2's projection of a 3D center of gravity to our planet's surface. For now, lets ignore all the other problems (e.g. does calculating a "center" really help answer useful questions).
The 2D projection only shows "non-radial" movements (e.g. shifts not pointed towards the earth's core). For example, if the center of gravity moves directly to the other side of the planet, the 2D projection won't change until the 3D point passes through the core, at which point the projection would jump wildly to the other side of the planet.
This is probably quite similar to what has really happened. I'd expect that the westward shift from AD 1 to 1950 had much to do with the growth in the Americas. Afterwards, I'd expect growth in India, China, and Japan moved the center eastward.
The 2D projection only shows "non-radial" movements (e.g. shifts not pointed towards the earth's core). For example, if the center of gravity moves directly to the other side of the planet, the 2D projection won't change until the 3D point passes through the core, at which point the projection would jump wildly to the other side of the planet.
This is probably quite similar to what has really happened. I'd expect that the westward shift from AD 1 to 1950 had much to do with the growth in the Americas. Afterwards, I'd expect growth in India, China, and Japan moved the center eastward.