system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do franchises like Call of Duty continue to do so well despite adding so little new content? 

Let me start off by saying that I am not a huge fan of FPS games (although I have had fun with Gears and Halo, as well as all the oldschool stuff like Doom, Quake, Half-Life, etc) so maybe that's what I am missing, but I just don't see the appeal of all these games which everyone is so fascinated with. The gameplay is exactly the same in every one of these; each new edition just seems like it puts a new coat of paint on the exact same game and sends it out the door selling you on things like "new maps" and "new weapons" which seem like they should be great as downloadable content, but not an entirely new game. 

The same thing goes for Madden and other sports games as well, although I can see that a little bit more as people want the players on their team to match their real life counterparts so they buy the new edition every season, despite the fact that it is basically the exact same game.

So what is it that keeps people buying these games? Is the gameplay experience so great that it doesn't matter if it just keeps repeating itself? Is it a lack of other quality titles? Is it more a case of successful marketing? I just don't get it.
gpt
Because new isn't necessarily better, nor is it what people are always looking for. Especially in video games, where it is difficult to build compelling characters and original plots. People want a new experience (new guns, weapons, environment, whatever) while simultaneously having the same familiar experience that they have previously enjoyed (gameplay, story, 'community', etc.). It's the same reason that movie sequels and the like are popular.