* Consumers do not pay money for each transaction of content they consume. Instead, they pay with their attention. But that doesn't work like a currency because their goal is not to minimize the attention they spend. It's burning a hole in their pocket and they want to give their time to YouTube.
* YouTube spends next to no money on each unit of product they deliver. After they show a user a video, they still have it.
So looking at this as any kind of supply and demand situation is going to just completely muddle the economics. The supply is nearly infinite and the "demand" is hard to even define.
Like, “oh we don’t have John Oliver anymore but here’s Redacted Tonight with Lee Camp! Everyone’s happy, right?”
Neither of those statements are true, but you seem to be commenting as if one or the other are.
I'm not arguing that the YouTube market is perfect, but that the gap between the average and most popular channels isn't so wide that the loss of some of the latter has a dramatic impact on their viewership. This is so manifestly and obviously true that I'm puzzled about any counter-examples you're envisioning.
Top brands -- like College Humor -- are never going to be happy on YouTube forever. The cream of the crop cannot be kept happy forever. If CH decides they'd rather keep 100% of X ad revenue instead of smaller-percentage of Y ad revenue, and that the math will work out in their favor, they're gone, and there is nothing YouTube could do to keep them. After all, why should CH work as serfs on YouTube's property when they can be lords of their own?
There are very, very few people who can make the math work, given the expense of supplying streaming video (which fortunately, CH has been doing themselves for a very long time already) and building/keeping an audience, etc, but there will always be some.
And yet, to my point, YouTube doesn't seem to be suffering. There's no way for YouTube to keep 100% of all video revenue, and it's possible that enough popular YouTubers acting in concert via collective action might figure out how to extract slightly more from YouTube, but most popular YouTubers are making more money from Patreon than YouTube themselves, and YouTube is still a big enough player that they can afford to wait out quite a few high-profile defectors, most of whom will come limping back after things turn out to be harder elsewhere than they expect.
Google knows what percentage of time is spent on big high-profile YouTubers vs mid-range and lower. I suspect the long tail is very, very long indeed. A Logan Paul might want to believe he's crucial to YouTube's success, but I don't think he's more than a tiny blip.