That's because he's the only guy who seems to understand it's his job to be an entertainer. He embraces this role and has created an amazing character that is always putting on a show. All these others streamers are just dudes in their bedroom playing videogames, or girls working as glorified camwhores who don't want to admit they're virtual strippers (if not outright pornstars).
Nobody in show business has to put out as much content. I remember when I was younger everyone would talk about how talk show hosts and late night hosts were the hardest working people in show business because they had to put out a new show every day nearly all year long. They have to put a lot into that one hour a night, but Doc is putting out some 30-50 hours a week. It's gotta be draining to don a persona that enduringly.
Also, LMFAO at the song at the beginning of that video.