Yes, I always thought it was the crust moving over a fixed hot spot, but I suppose it is also possible that the inner Earth is rotating at a slightly different rate than the crust, hence a moving hot spot relative to the crust. In fact, it probably makes more sense that the gooey mantle is sliding/spinning even more slowly than the more liquid core.
Absolutely makes sense. We keep looking at everything in 2D when in reality there may be more axis of movement we don’t understand and it should actually be viewed as 3D.