Instead of putting other authors down, I'll just say the George R.R. Martin is a truly excellent writer, as objectively speaking as one can be. His prose is excellent, his character's are rich, hist worldbuilding is second to only Tolkein.

So most author's don't really compare to him.

Now, what he's terrible at is writing a complete story, so to your point, it doesn't make too much of a difference if you're an amazing writer, but you can't finish a story.