Similarly, the people who buy games again and again are more likely to be playing first-person shooters or heavily-involved RPG games that don't lend themselves

Similarly, the people who buy games again and again are more likely to be playing first-person shooters or heavily-involved RPG games that don't lend themselves well to motion based control. Moving your whole body is simply too inefficient in comparison to using a controller. As a result, the motion controls are limited to "party games" that rely on simple gameplay rather than a deep experience.