The franchise has already died... quality wise.

I don't see it dying any time soon, I mean the fact that the daily player numbers of Blops and MW2 are so high shows that. As long as Activision can keep the quality up it should easily keep its popularity until next gen

As Machina wisely said, it will not die but just like any "fashion" it will decline over time, and the launch of new/better games from the competition will only accelerate this decline.

Also, please, stop comparing this with Guitar Hero. Activision killed it by launching 3-4 games a year! If they had done it right, it'd still sell well.

Any game series can decline, thinking that CoD is an exception would be naive. A game that gives the same sort of enjoyment CoD does, but better and fresher would probably do it. It doesn't even have to be an FPS.

Thinking that Final Fantasy has declined this gen is just wrong by the way.

I think after Modern Warfare 3 there will be at the most 2 more games in the franchise.

Was it ever alive?

All things perish. The final game will be interrupted by its instantaneous demise, the last man shall die without a funeral, the sun will fade out without an obituary, and the universe as a whole will either be ripped apart or crushed.

But in the near future, no. Call of Duty 8's preorders indicate that it may be the biggest entry in the series yet. I could imagine some franchise or another usurping it next gen, when the competition isn't so settled, but even that's no certainty.

What happened to Guitar Hero will happen to Call of Duty.