A whole lot of major YouTube channels who are constantly attacked by false copyright claims or have to push product placements due to no ads would love to push users to a better platform. So marketing wouldn't be impossible.
They could also push privacy and fine tuned data controls which helps with kids.
There's enough of a market for two to exist.
Maybe with some type of semi decentralized platform approach so individual hosts who deal with copyright poorly can take the hit, making the system more resilient. Chrome style apps and mobile clients could be the interface and the ad/patreon system is controlled by the primary software developer but the rest is an open protocol with a linear license for non commercial stuff (at least non commercial as far as not competing with the monetization platform). The network effects of managing the ad buyers, subscriber accounts with credit cards and one click subs could stave off the competition without fully controlling the full video network and hosts.