It gets.....
kind of complicated of all the various ways you can make money on YouTube. Yrs ago if you had a million viewers, you were guaranteed some income.
I know a musician who has a channel and he makes his money buy selling intellectual property that he's created. He's one those guys that never made it "big", but he knows everyone in the biz and they all like him. In music we sometimes forget that the world is full of session musicians/music teachers and not just 'stars'.
The guys with good channels will spend hrs just to make one vid.....it's a long process if you do it right.
Kevin