I think this will only end up with YouTube winning. Google has been caution for years, but they can bring the big guns if they see there are no more options. Google is clearly desperate to bring those numbers up and they don’t care if user experience suffers.
First, they can decide to deploy a restrictive CSP that prevents external scripts from running in the page. This would break lots of extension that work on YouTube.
And then they can just enforce DRM like Netflix. This will be horrible for users, cost them more to serve, and potentially break Youtube for older clients. But then ads will be impossible to skip, and downloading videos will because almost impossible.
But if they decide the numbers are worth it, they will do it. But honestly at this point I really don’t care. Will I miss YouTube? Sure. But I rather watch less content on nebula than support this horrible user experience.