Movie rights will be a big factor also. Events like TIFF, Cannes etc, while being a platform to show films is also where deals are done, distribution rights are signed always for different territories etc.
YouTube is essentially international which may invalidate some pre-existing licence and distribution agreements.
Youtube has the ability to limit videos to certain markets. One example is that the entirety of Mythbusters was uploaded in the past couple years, but isn't available to view in the US.
