When I mention continental drift to non-scientists, I often am asked if having the continents all together as they were 200 million years ago might have unbalanced the Earth. Surprisingly, the Earth's continents are closely bunched now . If you look down on Paris on a globe, you will see a hemisphere containing most of the Earth's land. The Earth is very asymmetrical, but a second surprising point is that the distribution of continents and oceans has almost no effect on the balance of the Earth. Continental crust is thick and high, but it's light.
Oceanic crust is thin and low, but it's dense.
This buoyant effect, called isostasy , in effect makes the Earth self-balancing. The plasticity of the Earth's interior has another important side effect. The centrifugal force resulting from the Earth's rotation causes the Earth to bulge at the Equator by about 14 miles. Changing the rotation of a sphere is hard, changing the rotation of an ellipsoid like the Earth is harder yet. The Earth has a lot of extra mass where it counts most.