This is a really interesting concept. What if developers had paid or ad supported official streams? Sure most people would block the ads or continue to watch their favorite streamer, but a non-zero amount of players might elect to watch the devs play the game in an effort to support them directly. And this would just be additive revenue compared to the zero they are getting right now on streams. It might even be synergistic as official advertisement for the game and as a way to connect directly to their community. I could see it also as a way to play a game but with director commentary on, similar to how movies do it.