Soul Society is only one of what I imagine must be countless destinations for the soul after death. Even for us, it is not truly an afterlife. It's merely another part of a cycle, and when we die in Soul Society, we eventually make our way back to the world of the living. Considering how varied the worlds here are, and how different even the ones that share a name and a time period have proven to be, is it not also likely that the ... let us say rules of life and death ... should be many and varied as well?