And there is one thing I'd like to put in, concerning COD. If one envy the success of that franchise, one should perhaps have a feel of why it has succeeded, and have a feel for the COD community feelings for the franchise. The last is said because gamers just aren't so universally enthusiastic about where COD is going, as some publishers and marketing people assume. So take this from a COD gamer (yes I confess

):
Many (theory based on me and everybody I know) COD players complain about exactly the same thing as players here complain about: Dumbing down instead of evolving. People keep buying the games because they know what they're getting, and they enjoy it
enough. But the only thing that evolves in COD is graphics.
I have all the COD games. I have played all of them completely through and out. But I have not played a single full campaign
twice.
Very important parts of COD is multiplayer and competition. These parts are enough to motivate a purchase of next game, in order to stay in touch with the community. This is true for both competitive players, and social players.
This should mean little to a RPG developer (outside the MMORPG perspective)
Mature RPG players are not (in my estimate, at least) very competitive. Competing is not the enjoyment they seek in RPGs. They may well be social, but online game societies tend to be rather dreadful experiences. Often they are dominated by teenagers sacrificing school, future professional life, offline social life, for a few years of full dedication to a game. Those teenagers often tend to be an abbrasive experience, at least to older players.
That people keep buying COD does not mean that they're happier with COD4 than COD1. It does not mean that they approve. Just that they want more of similar experience.
The quality of the first COD was atmosphere and historical accuracy. It had loads of that. As a single campaign shooter it was rubbish. And COD have not changed in that regard. If anything they've gotten worse, with streamlining like auto health-regeneration etc. A COD game is so linear and scripted that the main gameplay element is guessing what the developers intended you to do next. If you don't do that, the script and game will not progress.
What has happened with COD is that many of the games have abandoned historical and realistic accuracy for 'awesome'-effects. And that the background stories have gone totally overboard in idiotic absurdity. (Don't even get me started on Black Ops

or Modern Warfare 2

).
So how long will people keep buying COD games? I don't know. I'm certainly starting to get tired of what I see as diminishing 'seriousness' and realism of gameplay and story.
The COD franchise success is based on word of mouth and a clear recognition of what a COD game is. IMO, Dragon Age could have duplicated that success just by staying on coarse with DA:O. And done so on nice budgets and shedules, simply by keeping a lot of stuff. Instead they rushed Awakening, and trashed Witch Hunt, all so they could rush out a completely different Dragon Age 2 to a non-existant market.
Exactly what I've come to expect from EA

, but still mindbogglingly stupid.