I see the COD franchise appealing to people that haven't been playing FPS games for the past 15 years. Just like Halo, I don't see how the sequels bring anything new to the table. Fundamentally, this is the same exact game that we've already played to death.
But then again, I'm a sucker for multiplayer unlockables.
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Hudson: Maybe we got 'em demoralized.
A lot of people miss the first incarnation of a series and catch it on the second, taking notice via the hype of partisans. Basically what happened to me with L4D2. First was totally off my radar, but the 2nd I will pick up. This snowballs into a 3rd incarnation with much the same effect.
But unless an idea is able to incorporate new and exciting tropes, it's difficult to keep it going for very long. And increasingly in this modern age it's difficult to produce something that is attractive to a mass audience. Interests are fracturing left and right and the great thing is the market can accommodate them.
Thus, there'll never be another band like the Beatles of Michael Jackson, in all likelihood, because musical interests have fractured entirely. Musical fashion is perhaps not as important as it once was, and music is very accessible. So you have people like me just as likely to listen to the 'Goldberg Variations' one moment and a little 'Explosions in the Sky' the next, capped by some Billy Joe.
The videogame industry too began in such a way that the only games that could get off the ground were those which had mass appeal. Thus, they became huge, and widely known. Pacman, Asteroids, etc. Then the market began fracturing into genre, and people began to prefer different genres.
Now, we even have different genres within a genre, or genres within a single game! When a game offers solo, multi, coop--those are all frame-genres within a single game. I'm actually kinda surprised no one's hacked Chrono Trigger yet to make it a 3 player game with online play :P How awesome would that be.
So, the good news is, if you don't like this, just wait, something will come around you do like. There will always be the purist gems that arise, like Shadow of the Colossus, Mass Effect, or Bayonetta.