They could, but it would be suicide. It isn’t like music...multiplayer games or complex single player games really benefit from hands on, which requires purchase (or playerbase for f2p). Cosmetics and micro transactions for skins are the gamer equivalent of some person seeing a celeb wear a brand of jeans and wanting to wear it. Another company would swoop in and say “you guys can stream our shit for free”. I mean fuck, they currently PAY streamers to play their games on stream sometimes.
It is a completely different beast than an album or a movie. I love the movie Starship Troopers, but I’m not watching it a few hours every night for years.