I'd say it's real, but weak. The value to me of the next incremental YouTube content provider isn't very large. If one of my favorite providers leaves, I won't find it hard to follow them.
What they have is the only practical advertising-based monetization platform. That's the real moat. You can use YouTube to build enough of a base to then create a backup monetization base with something like Patreon, but I don't know how to get you to that point without starting on YouTube first.
It isn't weak. Not sure how you look for new content. In my case it is yt.com/feed/subscriptions. If you leave i might follow. But only if enough content is on your new website to warrant me opening that tab a few times a week. Maybe also with content very on schedule. But you can be sure I wont do this with many sides, so you better switch to the same platform as anyone else.
Also maybe once or twice a week I actually follow one of YTs recommendations. I'm unlikely to do the same on platforms with significant less content. I'd expect others to behave the same and thus you'd probably loose a lot of advertising. Being big on a smaller platform has its own advantages, but I'm not sure this cancels out. And you have to be one of the top dogs in the first place...
I'd say it's real, but weak. The value to me of the next incremental YouTube content provider isn't very large. If one of my favorite providers leaves, I won't find it hard to follow them.
What they have is the only practical advertising-based monetization platform. That's the real moat. You can use YouTube to build enough of a base to then create a backup monetization base with something like Patreon, but I don't know how to get you to that point without starting on YouTube first.