To my mind, there is a wonderful sweet spot halfway between the mainstream and the avant-garde, a place where fascinating things happen. This is where left field bands go to record their "pop" album, or quirky Jewish filmmakers decide to make a Capra-esque comedy. Tempering our artistic ambitions in order to actually make some money can be so much more than just "selling out" - popular culture is constantly driven forward by this commercial cross-pollination.
Take My Chemical Romance's The Black Parade as an example. This is an album that is both wildly experimental and deeply indebted to classic rock, welding jagged emo to the kind of guitar riffs that would have Brian May nodding his shaggy perm in approval. A concept album all about death that is somehow uplifting, a furious screaming metal album that is also incredibly tuneful - truly a contradiction in terms.
In the TV realm, consider Glee. It is a show full of mashups of popular songs that is itself a mashup - High School Musical with added irony, social comment, mawkish sentimentality, sharp comedy and will-they-won't-they sexual tension. It's an exuberant mix that doesn't always work, but is riveting even in its failure.
Across the film world, there are almost too many examples to pick. Hollywood delights in stealing ideas and directors from the world of indie movies and twisting them into commercial projects. The entire canon of Judd Apatow and Kevin Smith pretty much fits into this category. Sam Raimi, Peter Jackson, Christopher Nolan - these are all directors who started out making humble, innovative movies for themselves and somehow ended up with multi-million dollar franchises. I defy anyone to watch Spiderman 2 or the Dark Knight and tell me that art, money and entertainment can't coexist.
Children's writing provides a perfect arena for this kind of cautious experimentation. Our market is composed of readers who have - if you'll pardon the phrase - a very low threshold for bullshit. On the other hand, we writers struggle to get noticed without some original hook to our work.
My first attempt at a teenage novel was a bit of an experimental hotchpotch, with a deeply metafictional plot, characters who were conceptual artists and a whole chapter written as a screenplay (with all of the scenes in the wrong order). Unsurprisingly, I felt the need to meet the market halfway for the next one. I'd shown an unexpected talent for horror in the earlier book (yep, told you it was a mess), so zombies seemed like the perfect vehicle. They are both scary and funny, as well as being trapped in a moribund genre which is ripe for reinvention. As Joss Whedon discovered with Buffy the Vampire Slayer, such conventions are crying out to be messed with.
As a bonus, genres provide a wonderful shorthand - I've lost count of the number of times I've been introduced to someone in the industry as "the zombie guy." Long live the undead!