"I suspect whatever minor financial penalties his publishers might impose (beyond not getting money when the book came out) may have been dwarfed by the decision to sell to HBO resulting in the books selling approximately ten times what they had one prior to the TV deal"
Absolutely true! I remember reading GOT in 1998 and no one was talking about it. Only after clash of kings came out did the series have any kind of internet awareness, and only after storm of swords did the internet actually start asking when the next book would come out. But even then, the crowd that got upset at the long wait for feast of crows was still a small subset of the geekverse (i.e. geeks who like fantasy vs scifi etc). It was only after the first season of GOT aired that I noticed my non geek friends and associates would talk about it, and yes, I admit I was one of those obnoxious people who felt superior over the TV crowd because I knew what would happen..until now.
But absolutely, we all know people who decided to read the series after watching the show..hell, if I hadn't already read them I would have. Its a great adaption for the most part and it helped sell more of the books. I would guess the publishers are disappointed but the flip side is that is that they know as long as the books get done before the Tv show is over or soon after they will still sell well.