George R. R. Martin in an interview with the New York Times:
Did you conceive of “A Game of Thrones” as a reaction to Tolkien’s “Lord of the Rings” novels?
I always wanted to do something in epic fantasy. But not just to rehash Tolkien. I wanted to do something to make it my own. To some extent, the project was also a reaction to my own Hollywood career. I was out there for 10 years, from roughly 1985 to 1995. I was on staff on “The Twilight Zone” and “Beauty and the Beast” as a writer-producer, and then I did about five years of development, doing pilots for shows of my own and some feature film scripts. The theme of that whole period for me was, I would always turn in my first draft to whatever network or studio or producer I was working for and the reaction was inevitably, “George, this is great. It’s terrific, it’s a wonderful read, thanks. But it’s three times our budget. We can’t possibly make it. It’s too big and it’s too expensive.”
Then what would happen?
So then I would go in and I would start cutting. I would combine characters and trim out giant battle scenes, make it produceable. Although the later drafts of those scripts were always more polished, because I’d revised them several times, my favorites were always the first drafts, which had all the good stuff in it which I had to take out because it was too expensive and too big. When I returned to prose, which had been my first love, in the 90s, I said I’m going to do something that is just as big as I want to do. I can have all the special effects I want. I can have a cast of characters that numbers in the hundreds. I can have giant battle scenes. Everything you can’t do in television and film, of course you can do in prose because you’re everything there. You’re the director, you’re the special effects coordinator, you’re the costume department, and you don’t have to worry about a budget.
“ … because you’re everything there.”
August 2012 update —
Do you think there will always be a place for the big novels that you write?
Oh yeah. There's no doubt that the medium is here to stay. People like big stories. You get unmatched bang for the buck writing stories. The bang in this case is being able to plant a big universe and a lot of powerful images inside a reader's head. The buck in this case is that there's one person working alone without needing any special tools. That's not going to change. They may be delivered in different ways, on e-readers or whatever, but they will be around for a long time.
April 2011, San Francisco