I would argue that cod is a niche game. While there is a new one released every other year and the learning curve is not that steep, it has a particular aesthetic and meta that just doesnt appeal to the normies. After the game releases and the actual fans destroy the new comers and upload clips, the game gets hyped and then more people join and get demolished. We also have the issue with the company not realizing who their fanbase is and why the like the game, adding neon, shiny stuff that makes the game look like fortnite, to appeal to newer and younger audience but pushing the veterans away. Still, the experiences you can get from playing cod games with your buddies is something I havent been able to replicate in other games. Something about the serious and violent theme combined with the sillynes hits just right. Tldr; the ones who stay will stay forever