Plume–ridge interaction is an intriguing geological process in plate tectonics. In this paper, we address the respective role of ridgeward vs. plate-drag plume flow in 2D thermomechanical models and compare the results with a compilation of observations on Earth. From a geophysical and geochemical analysis of Earth plumes and in combination with the model results, we propose that the absence of plumes interacting with ridges in the Pacific is largely caused by the presence of plate drag.