It's funny how naive youtube content creators are. They complain about their subs not getting their notifications and ask their subs to hit the "notification bell" as if that is going to do anything. They don't realize that youtube is being pressured into moving away from individual content creators to corporate content. You don't see john oliver, jimmy kimmel or SNL subs complaining about not getting their notifications.
HBO, ABC and NBC aren't just content creators. They are subsidiaries of large corporations who are also some of the biggest ad spenders.
It's isn't by accident that john oliver, jimmy kimmel, SNL, etc are so heavily promoted by youtube.
It's in youtube's interest to manipulate the notifications system so that when john oliver releases a video, his views do well since he is advertiser friendly with the corporate seal of approval. But in the long run, this could be very bad for youtube as people's interest declines. It isn't corporate content that brought people to youtube, it was local/individual content.