Call of Duty died like a month into release on PC every year until they made it cross platform. That always confused me, why it never translated from console juggernaut to PC in the PS3/Xbox 360 era.
I couldn't tell you. I only really got into the early COD games. I think maybe there is a mixed reaction with cross platforming. For instance, when the Halo pack came out on PC people were complaining about the advantages/disadvantages of controller vs keyboard/mouse. Though if you want a healthy game, it makes sense to have more players.
I think maybe there is something to say about matters of taste as well. Simulation warfare or arena shooters are popular on PC. Historically games like Quake, Doom, Team Fortress, Counter Strike...stuff like that. Or simulation like ARMA, Hell Let Loose, Squad. Or other games like Escape from Tarkov. Or the days of Return to Castle Wolfenstein multiplayer. (I used to play a ton of that.)
I'd say Battlefield is likely more popular on PC than COD. I kinda drifted away from that sort of shooter. I like simulation mostly if I play any shooters. Prefer the more tactical, slower pace, realism.
There is a channel I've been watching for years, a guy named dslyecxi. He has his own outfit on ARMA that do actual missions together. If you die, you're gone. The missions are well planned out, but sometimes it can be unpredictable in the most funny ways. They did one simulation a long time ago of a Vietnam era map. They limited the tools they usually use. To where only certain voice channels were open, like their command element. But the teams had to rely on runners to relay messages mostly. At one point his team scaled a mountain and they I guess didn't read the terrain right and a bunch of guys fell to their deaths. lol
https://www.youtube.com/c/Dslyecxi
I haven't owned a console since the days of the first XBox. I really just like PC gaming. I'm really into strategy games. Like the Total War series. The historical ones like Rome I and Rome 2 - Medieval 2 - Shogun 2 - and the fantasy ones of the Warhammer series.