It won't die until something else catches the markets attention as a cheap way to make the most cash. As much as people like to boast how much video games are made by people who just love the medium, there are equally as many people either working to put food on the table, or making games with the intent of raking in as much money as possible. The same is with any other medium. It used to be platformers were THE THING. Then 3rd person shooters were THE THING. Now FPS is THE THING. Especially when its flashy. MMS is easy to emulate because it resonates with people. Automatic guns, manlyness, flashy action sequences, and against DEM TURRORISTS. It has brand loyalty.
CoD is fine. It works. You shoot the things with the guns and they die. You're gun works well, and there are many types of them. Mechanically, the game works well and is decently balanced. The game isn't horribly broken - on the flip side, its intensely polished. Iterative as balls? Yeah, but little to no iteration has been a staple of a lot of franchises that are beloved.
Its an issue of taste. I don't like the game. I don't like the playstyle, and the community is toxic. The mechanics don't feel very skillful to me, and I find modern military settings boring. It's a decent popcorn game, but eh. If other people like it, it'll flourish. It won't die until the market either shifts, or people get tired of MMS - or both.
Frankly, I don't mind its existence. I don't think its existence hurts the games industry. Certain companies will ride the bandwagon to make some extra cash, regardless of what THE THING is. I think the focus testing aspect of the industry is the danger, not the games being made.
And for anyone who thinks Call of Duty can't die - Guitar Hero and Rock Band. Granted, those involved a larger upfront investment, but still. Huge, casual hit. Spawned an entire genre - it was dead within 5 years. CoD isn't pumping out as many titles as Guitar Hero was, but sales have dipped, and people will get tired of the cycle of spending $60, then another $60 on map packs, every single year.