Valve / Steam presumably has good data on what controllers and peripherals people are using, so I'd imagine their port choices are based around that. Here's a June 2024 post talking about Steam Input and controller market share: https://steamcommunity.com/games/593110/announcements/detail... . At the time of the post they say "59% of sessions are using Xbox controllers, 26% are using PlayStation controllers, 10% are on Steam Decks"