Steam is only a distributor and package-manager/launcher. It's up to the selling company whether the game will have DRM-mechanisms. As I read, half of the fames are already DRM-free, not sure whether it's really true. There is also GOG which is a store dedicated to selling only DRM-free games.

Sadly, they have their own package-manager/launcher too. Same goes for blizzard, twitch, EA, epic games... Sometimes I wonder ifvthe world wiuldn't better with sone kibd of centralized digital-content-managment platform, and all those stores and launchers just tap into it.