[apacheCamel]

I think it is a little bit of both. IMO, it seems to be along the lines of how big the channel is. The bigger the channel, the more room and flexibility they have to move around games because the fans are more there for their personality than the game. Lower end channels don't have that freedom. It is almost like their fans are there for them, but only playing that specific game (whether it be for their skill in the game or maybe their knowledge of it).

[riffraff]

I'd say the game is the "genre" and the streamer is an author. If you are someone who produces music or literature, and you do it in a popular genre, you will get some of the genre's public through radio streaming, antologies etc.

If you are good enough, people will buy your next album/book in the same genre. If you have a cult following, people will buy your next book/album in whatever genre.