I'm gonna be the first to be so bold and predict that GRRM will NEVER finish Winds of Winter or Hope/Dream of Spring. It's five years and counting and Winds is still nowhere near done according to Martin. And this is after he re-structured the ending to Dance with Dragons and cut about a hundred pages from that book, moving those pages to the beginning of Winds to give him a head start. And with the HBO series breathing down his neck.
Let's say Winds manages to come out in another year. I imagine GRRM will then take maybe a year or two "off" from the series to re-charge before making the final push on the ending in Spring. Since Spring will be the grand resolution of this sprawling saga, I can imagine it will take longer to write than any other volume thus far. Since the last few books have taken about five to six years to produce, that means Spring might take GRRM close to a decade or more to write. I really don't think we can expect to see Spring anytime before 2030! The man is 67 years old. I haven't read of any health problems but he does appear obese. Just the normal decline of aging is undoubtedly going to affect his concentration and creativity and slow him down further.
And I'm fine with this. I realize GRRM is "not our bitch" He doesn't owe us another book.
But I also don't care anymore.
Half a decade is really far too long between installments of a story as complex as Fire and Ice. If it wasn't for the TV show, how many people would remember all the plot points between volumes. We have lives. We read other books. We see movies, follow TV shows, comics, politics. A Dance With Dragons really should have had a synopsis of the preceding volumes printed in the front. Who has time to go back and re-read these massive tomes every five years to re-fresh one's memory, no matter how much we enjoy them???
So for me, the TV show is now the story. IF they ever do come out, I can't imagine reading the books after seeing the ending on GAME OF THRONES. I stopped reading novelizations of movies and TV series as a teenager. And that's all the final two books are going to be now. Just glorified, lengthy novelizations.
So here's to A GAME OF THRONES. A great TV series that totally has eclipsed it's source material.