YouTube is probably a bad example in terms of copyright. They in fact have the most restrictive system of reuse of others work in your work, as a large portion of the videos that are auto struck would probably err more on fair use.
So they're actually incentivized to have many creators struck, because struck media means ad impressions whose revenue they need not share.
Am I misunderstanding the landscape?
This revenue would go to the copyright claimer. EG if Warner bros struck you for showing their movie, the ad revenue from the video would go to Warner, not simply YouTube