Uh ... I'm saying that the game might not have a "main quest" that's not derived from the PCs' interests, desires, and/or needs; and if you do not have such a thing, you can't just "pick up the main quest of the campaign" with all new characters with no connection/s to the old ones. Dealing with the death of a single PC is definitely easier, if you're basing the goals of the campaign on what the PCs need/want, because you still have N-1 PCs with existing, ongoing needs/wants. Is this controversial?