EA (Origin) and Activision/Blizzard (Battle.net) have their own launchers and don't publish on Steam. But while those are some of the biggest brands it's a tiny portion of the overall industry: maybe 4-10 dozen exclusive games in Origin + Battle.net + Uplay + Epic Store, but a few thousand on gog and a few tens of thousand on Steam
Discord is/was a games launcher too and they just shuttered their subscription service as nearly no-one was playing the games that came with it.
Huh? I thought saying you can't sell on Steam is kind of what an exclusivity contract with Epic does.
- If you put up a Steam Store page, you can’t release the game earlier on another platform. - Any patches/updates must be released for Steam at the same time as they are on other platforms. - Games can be released on other platforms, but you can’t put up a Steam store page until 30 days before the Steam release or the game’s original release, depending on which of the two is earlier.