Then why are you GMing. Trust me, I've seen some shitty writers, and you're not one of them. And even then, I sometimes learned from shitty writers. I'm probably one of them, anyway. You can learn from anyone. 

What you're saying is like saying you can't learn from children, and you can learn more from children than you can learn from some other people. Everyone has stuff to teach, you just need to find it ;)