He didn’t say valve created DRM he said that steam pioneered it. Don’t revision people comments.
Had to google “pinoneered”, but it say: “developed or be the first to use or apply” and i do not think valve did either.
They have an easy way for developers to implemet drm by require steam services tho.
But in my opinion it is better there are few well understood methods instead of a million uniqe ones. Incase there is a world this have to be reverse engeneered.