RightersBlock, to answer your second question... "Were the books popular before the show?"
Take a look at the page just before the GRRM forum, the
Author's Page. Of the 38 authors listed, GRRM has both the most threads (1,156) and the most posts (47,657, including this one) by Chronicles users. I know not all of them are positive comments, but the author with the second most threads (446) and posts (20,656) is only the venerable Professor Tolkien.
Since the start of the show,
a new page was created on the Chrons for discussion regarding the show without interference from the series readers. It has 97 threads and 1,644 posts.
Also, ASOIAF was translated into at least twenty-five languages before HBO purchased the rights to the show.
As for your first questions, "Do you think the GoT will have any lasting power? This applies to the whole franchise it self. Or do you think it will wane and ultimately be forgotten or looked on negatively?"
What is your time frame for "lasting power"? Ten years? Twenty? A hundred? Five hundred? Due to the fact that GRRM will not finish the series for at least six years, I'll say it will be regarded as a monumental epic in Fantasy in the year 2034. Given it's size and graphic nature, it will never be included in a high school syllabus with
To Kill A Mockingbird,
The Odyssey,
The Scarlet Letter, or
The Adventures of Huckleberry Finn. (My apologies to other English speakers because I have no idea of your required reading in school.)
In fifty years, I think ASOIAF may be considered one of the foundational works for huge market for adult fantasy... and I don't mean porn. Let's face it, this is not Narnia. Bilbo and Harry Potter have no place in Westeros. This is a tale of Stannis, the Kingslayer, Cersei, Catelyn, Eddard, Theon, and Victarion. Sure, there are kids in the story, but they don't magically succeed over adults. And there are teenagers too... but I think they experience more mistakes and heartbreaks than victories, e.g. Theon, Jon, Dany, Sansa, Robb, and Joffrey.
How many people saw John Carter of Mars? Not many. How viewers knew there was a phenomenally popular series about John Carter ninety some years ago? Probably not very many. In a hundred years, Jon Snow will probably be viewed as most people view John Carter now... out of date and irrelevant.
Will ASOIAF stick around for a few hundred years as Dumas' stories of his musketeers? Will the socio-religio-political commentary be forgotten and will the series regarded as a grand epic? Will Jon be compared to d'Artagnan? Will Dany be compared to Dantes? Maybe, but probably not.
Will historians revere Martin after his death like Shakespeare? Will he be considered as influential to our language as The Bard? No.
In three thousand years, will people speak of GRRM as we do of Homer?
Kiwi, I'm hoping GRRM will wrap it up in another two installments... for the U.S. edition.