In the post five movies are highlighted, Wonder Boys, Throw Momma From the Train, As Good As It Gets, Adaptation, and Deconstructing Harry. It's a fun article to read if you've seen these movies and P.J. Parrish does a good job of making them relevant to actual writers.
The line that is mentioned for Throw Momma From the Train is a favorite of mine and i'm glad it's pointed out so well in the post.
I think the better question is, why are movies about writing and writers so mediocre and/or bad? I've seen Wonder Boys and had to force myself not to yawn. I hated Throw Momma From the Train despite the fact that most of my friends loved it. The fact that Jack Nicholson's character was a writer was unecessary and was really only there for him to provide a memorable line. I fell asleep during Adaption and still don't know how it ends and I've never seen Deconstructing Harry.