The thing is, consumers are still encouraging the hell out of this franchise even though it is well past its prime back with the 4/5/6/7 games. Every other game since seems like a tacky addition that's pretty analogous to the passing years of sports franchises, offering only a handful of new "features". I honestly feel like the whole peer pressure deal is playing in to why this franchise is still milking the cow and still getting a lot of return, since everyone wants to have the new one to play with their friends. It's a nasty snowball effect.
I personally have no qualms about the gameplay of the 4-7 games that I've mentioned before. Aside from painful balance issues (hello to the three guns per game ever used competitively), the game is a fun and relaxing - as long as you don't take this **** seriously, please don't - arcade-style, fast paced shooter which is fine for a quick casual gaming session over the likes of Battlefield or Halo which require more skill and tactical activity which isn't terribly casual-friendly. Of course, each game has its exceptions. Competitive Call of Duty was actually fun to play and watch, and required immense awareness and skill at times. Halo's got Action Sack and Customs/Forge, and Battlefield has some of the best ways to troll people. But in general, CoD is a fun, casual shooter which appeals to the masses and I have no problem with that, and I have no problem personally with the games themselves.
Where I think the franchise is lacking though, is the community and the regurgitated games Activision ****s out year after year with very little to offer in terms of improvement or innovation in gameplay. Not to mention the absolutely repulsive community that can only be overshadowed by voice chat in League of Legends ranked queues. If Activision spaced out the games like Microsoft had Bungie do, we'd see a huge increase in quality and maybe, just maybe, the game would be fresh and exciting every time it comes around like Halo. But they won't, because they're busy drowning in the money of helpless consumers and they don't give a **** about the quality of the games as much as they do the money.
That's why I hate CoD.