Mobile First, Right Thumb Navigation

To be more thumb-friendly, why shouldn't we consider placing navigation on the right? Roughly 90 percent of the world is right-handed, so wouldn't this make more sense? The most easily swipeable area for righties resembles a rainbow starting from the bottom left arcing toward the top right of the screen. Below that rainbow is a thumb/palm blind spot, above that rainbow requires a user to shuffle the phone in the palm and a thumb extension to reach. The taller the screen, the larger that area above the rainbow becomes and hence more difficult to navigate. Even the smaller-screened phones such as the first-generation iPhone, have this less-reachable area.