It's called confirmation bias. You believe the game is dead and you are trying to bend the facts to support that idea.
Class discussions mostly take place at class discords, as well as smaller content creators on youtube discuss them a lot. For example the main warrior oriented youtuber has like 6000 subs.
When it comes to the mainstream, Preach is doing some class videos, but the classes are supposedly changing a lot every week and thus maybe it's not worth making the videos because they get outdated to soon.