Because the only people who use Steam are those who are happy with it. People that don't like Steam can use the Microsoft Store, Epic Store, Origin, GOG, the Ub

Because the only people who use Steam are those who are happy with it. People that don't like Steam can use the Microsoft Store, Epic Store, Origin, GOG, the Ubisoft Store, buy physical copies, etc. so they probably just do that instead of complaining about Steam. And the same goes to publishers, in fact many of those stores were created by publishers that weren't happy with Steam's cut.