How do music genres effect the creation of music?

Have you ever wanted to hear a perfect fusion of 70’s Go-go, Metalcore and Dubstep? I have. I have wanted it so hard. But even if it does exist, I don’t know how to find it. I don’t even know what it would sound like if it existed, (besides awesome.) Which leads me to my question: how does genre effect the creation of music?

From my incredibly abstract (non-existent) understanding of basic music theory, the actual “rules to music” are not directly related to genres in any real way. If that’s the case, why such a strong divide between them? Money? It’s just money, isn’t it. Vendors need marketing, producers need vendors, artists need producers. Is that it? Genre makes it easier to market music?

I mean, I’m sure artists have their preferences that they identify with different genres, and that effects their musical inspirations; but how much of what a musician becomes is determined by raw musical inspiration and how much is determined by arbitrary rules set by genre classification?

It’s nice to think that musicians fly off into the cosmos, create their music with their divinely chosen instruments, then rain it down upon us; and it’s just us that divides it up into our little categories so we don’t get overwhelmed. But “we” are the musicians sometimes, so how could that be?

How would things be different if the line between science and music were hazier than it is now for the average talented musician? Would the “genre rules” be overridden by more natural musical rules? Would music be more diverse? Would we get to “rock” it to Gogo-metalcore-dubstep?