The reason we don't know is because the writers don't know. No one sat down with a lore encyclopedia and the scripts for the last 4 expansions and whiteboarded / flowcharted out the ramifications of any of the lore or story reveals in DT. It just flowed out of the end of a pen based on whatever beat gave the writer his or her best feels in the moment. You CAN"T analyse the lore like a scholar because it has no fundamental structure or logic.