Great writers aren't limited by genre

I've just seen a posting on Screenwriting Staffing from someone looking for a screenwriter to doctor a horror film script. This person will only entertain screenwriters who are passionate about the horror genre, and/or have more than one horror screenplay credit. Why? A good screenwriter doesn't need to specialise in any genre. The same screenwriting instincts (story, structure, narrative) and screenwriting techniques (nuanced, dynamic screenplay characters, ellipsis, enter scenes late and leave them early, minimal dialogue etc.) can be applied to film/TV scripts in any genre. I think this is just one more way in which producers etc. disavail themselves of good screenwriting talent. Consider the great fiction writers and playwrights. Were they limited by genre? Exactly.

Of course this brings us to the perennial question: does screenwriting attract great writers? It's been suggested that it doesn't; that screenwriting is a lesser form than, say, stageplay writing, novels, short stories etc. I suggest that the screenwriting form needs great writers very much. This, however, brings us to another useful question: are there enough people in the film industry - agents, producers, directors - who know great writing when they see it? (I'm using the word 'great' in its literal form here, not the abased form more generally used).

Answers on a postcard please . . .