it has no ties with "the purpose of youtube" simply because... it's not youtube.
It's literally hosted and watched on YT my guy. Without YT the video would not exist, without YT the video would not be watched, without YT the video would not even get created, and without YT it would not give the creator any way to monetize it - be it through YT ads itself or through external third party sponsoring, which is ultimately completely irrelevant to your counter argument. In the end the videos get made with the purpose of making money off of them, not to provide a potentially interesting video to be shared with others - that's how YT started.
Sure but if the content suck you won't watch it.
I won't, thousands or even millions of others do though, because the average user is about as brain dead as the content nowadays on YT.