Don't get me wrong, I'm not defending Youtube's behavior here. It's bad and shouldn't just be shrugged off. I just don't think that shouting "monopoly!" actually fixes anything. If you want a video hosting and streaming site that has less market dominance and better moderation policies, that already exists. Everyone is free to use them.
That's very much the point: collaring and tranquilizing the 900 pound gorilla in the room so that the reasons people might have to interact with the 30 other monkeys become relevant.
You need to address the underlying causes of this kind of behavior.
Some of that would be alleviated if we separated hosting/serving videos from the frontend and indexing, perhaps with a radio-like agreement on what the host gets paid for serving the video to a customer of the frontend. Frontend/index makes money off ads, and then pays some of that back to the host. Creators could in theory be paid by the video hosts, since views make the host money.
Then heavy handed moderation could be a disadvantage then, because they would be lacking content other sites have (though some of that content would be distasteful enough most frontends would ban it).