I'm not sure where I heard this advice recently, but it makes so much sense that I had to share it with you (in an illustration no less)!
What does this mean? It means that if you're doing audio book narration, and you want to do commercial work, you should include some commercial examples on your demo! Nobody is going to listen to your genre demo and think to themselves, 'this guy (or gal) should really be doing this other genre.' No one is going to discover you that way. You have to make them see you! Find a few scripts in the genres you want to tackle, and start recording. Good luck!