I think suggesting that Valve need any given game (CoD) or even genre (“games like CoD”) to remain successful is silly at best. Of course Steam, the Steam Deck, and as a result Valve are only successful or even exist at all because of video game studios and publishers. But Call of Duty specifically? Nah man, it’s a blip on the radar for Steam.
I’m not specifically talking about CoD or CoD-like games. I am talking about Non-Valve-Games. This is what Microsoft is arguing at its core when it says Valve was successful without CoD. There is a strict argument to be made that no, no they weren’t successful without CoD or third-party games. They likely couldn’t have broke into the console marketplace and arguably maybe they didn’t even break into the console space, PC gaming broke into the console space. Either way, you look at it though, games provided by Sony, Microsoft, and other AAA games made Steam successful. Steam would not have been successful if they didn’t sell CoD games and games of that status.
