In terms of worldbuilding Tolkien can tell you what Frodo's great-great-great-great-aunt had for breakfast ten thousand years ago and why exactly that particular bowl of porridge was chosen, and that's great with the level of detail it has and how it makes the world feel realistic.
ASOIAF tells you what you need to know about the world pertaining to the events that currently happen. I don't know who Tyrion's distant ancestors were but I know who his grandfather was and how that affected his father who in turn made Tyrion what he is. With GRRMs writing it all serves his characters in the present, and to be honest I think most of his characters are more interesting than the vast majority of Tolkien's.