Then why is one of my favorite subgenres pretty much nonexistent from screens big and small? I'm talking about urban fantasy. UF is a huge market when you're talking about books. Type the phrase into Amazon's search box and hundred of thousands of results pop up. For the uninitiated, urban fantasy simply means that the story features traditional fantasy elements in a (usually) modern urban setting. Fairies walking the streets of Minneapolis. A whole other city with it's own laws and relationship to magic lying below the below the streets of London. A seen-it-all wizard negotiating treaties between warring factions of mythical treaties in a pub in Chicago. That is urban fantasy. Though of course there are infinite variations.
The truth is that urban fantasy is all over popular entertainment right now, but it's hidden in plain sight. Nearly all super hero movies take place in big cities. And most recent paranormal movies and shows have been about the vampire or werewolf or what-have-you trying to blend into the modern world. They take the element that most defines a fantasy, magic, and call it super powers or a monstrous curse or a genetic mutation. The Syfy channel's Lost Girl is the only show I can think of at the moment not hiding what it is.
Two of my favorite urban fantasies, the Dresden Files and Neverwhere have already been television series. However both were severely limited by budget constraints. The Dresden Files show became little more than a police procedural with a minor magical element per case. While Harry Dresden does sometimes work with the Chicago PD in the books, the scope of the stories is much broader and often sees Harry and his crew traveling across dimensions and battling monsters that would need a Guardians of the Galaxy level effects budget to realize. Neverwhere was actually a BBC miniseries before it was a book. Neil Gaiman, who'd written the screenplay, was disappointed that what wound up on screen didn't match what he'd imagined (the original Neverwhere show while not without it's charms, makes the Dresden Files show look positively bug budget). He adapted it into a novel so his vision of the story could get out there. It's been at least a decade since either was brought to the screen. The time is ripe for adaptations that will truly to bring the books to life.
But those are just the tip of the urban fantasy iceberg. Hollywood has literally thousands of books to choose from. Someone just has to have the guts to be the first to take the plunge, like Peter Jackson was for high fantasy. Once the floodgates open, who knows what tricksters, ogres, and gryphons will fly out?