RawSteelUT: GOG is the number 3 store behind Steam and Epic,
no f*ing way!!! if you mean store as in selling games, overall, like a real store, not even close.
in my pretty good educated opinion it goes like;
steam
origin/ea
uplay/ubisoft
microsoft windows store (or whatever it is now unless dead/abandoned)
epic
blizzard/activision (even what's exclusive and not also on steam etc. maybe like latest cod? etc..)
humble store (not counting bundles!)
green man gaming
fanatical (not bundles but just outright single games)
indiegala (not bundles but just outright single games)
gamersgate
{something else i forgot}
gog
itch.io
etc..
RawSteelUT: you'll never see a new EA or Ubi game here. Steam is the only store with the clout for those two companies
tee hee. little do you know. ea just returned last year (or around that time, not worth me checking exactly when) after EIGHT YEARS gone. (left after some DLC fight. yes, most existing ea games stayed, sure, but no new ones. so for all intent and purposes ea fucked off steam and very interestingly came back eight years later) there is a story behind this for sure. someone (either gabe or ea, i think gabe) got on their knees and sucked, HARD!!!
as for ubi, did you not know? they pulled an "EA" and are gone (for any new releases, again, they too keep old stuff there, but so what?) since 2 or so years. will they return some time in the future? well, now that we have the EA story, yes, it's possible. but for now, and last 2 or so years, ubi be gone from "all powerful" steam, buh buh ubi!! personally i hope not, because it saves me money. yes, i love the far cry games and most all ubi major games. so them being gone, saves me dosh. though interestingly their latest versions for all their main games i actually honestly (not just posting b/s, or signaling) hate/dislike. watch dogs 3 is sjw cucked b/s rancid piss. kinda same for asscreed valhalla. that one more, the setting, for me, is crap. england shmengland. but it too has "strong" female leaders and all that diverse pukefest so yuck,
tldr; ea "just" returned to steam after eight years (very strange and interesting if we ever find out the real story) and ubi left around two years ago.