I think certain games dont even bother to optimize the install size so that you cant fit other games on the hard drive, I think COD games are regularly hundreds of gigs
Having a humongous game might be a competitive advantage in the era of live-service games.
Users might be more hesitant to switch to another game if it means uninstalling yours and reinstalling is a big pain in the backside due to long download times.
I've often seen people mention that one reason for games like Call of Duty being so enormous is optimising for performance over storage. You'd rather decompress textures/audio files at install-time rather than during run-time, because you download/install so infrequently.
