Excellent article. One of the best examples I have seen of this is an instructional wood worker named Steve Ramsey. He has excellent content on Youtube but almost every video he makes has a call to action to buy his complete video sets on his website. And, for me at least, it worked! I knew I'd be getting excellent content beyond the scope of what was available on Youtube (eg, complete with PDF plans, cut lists etc) and he charged a very fair one-off fee, not a Youtube recurring subscription.
And now, his viewership is drying up due to changes in the Youtube algorithm (and his lack of posting, caused by the algorithm preferring a style of video he's just not interested in). But he is moving a lot of content to Tik Tok and other platforms, and continues to drive viewers to his own kingdom.