Board Thread:Lore Discussion/@comment-24282559-20140101205811/@comment-24358064-20140102172456

My take used to be that canonically, every quest in any given game happened, but they were not necessarily done by the player character. For example, in Morrowind, if your PC joins House Hlaalu and rises up through the ranks, doing all the quests, at the same time there were people rising through the ranks of Houses Redoran and Telvanni, doing all their quests. This theory took some damage from the Neloth case. Nonetheless, I'm inclined to still hold to it, and to agree with SotS that the Neloth thing is just a mistake by  Bethesda. In any case, one case is not enough to make an argument anyway.