If cod continues to be milked try be being the same damn game over and over again, and if a truly innovative and incredibly fun game comes out that is also "hardcore" enough for cod's "I wanna be in the cool kids crowd!" demographic, then yes, it's possible for a game to kill the cod series.
(please note that I am not hating on those who play cod. Just those who are the typical "COD IZ SO HARDCORE IZ THE ONLY GOOD GAME CUZ SUPER REALZ, AND IF U DON'T PLAY U SUK!!!" kinds of gamers.)