I was thinking about replaying Red Dead Redemption again, and the question popped into my head.

Also, after replaying the first couple of Bioshock games I found myself thinking about the days when single player campaigns —first-person games in particular— went on forever. Like say 1995 to 2004 or so, starting with Dark Forces and peaking with Half-Life 2, just before the Halo/Modern Combat model really kicked in, where the single-player game is just a kind of dry run for what you can do in the multiplayer suite.