Prove me wrong, then. You know what happens in books 4 and 5. You know how long he took to write them. Tell me that he hasn't written himself into a corner, is trying to get out, and had no idea what to do so he just started pulling stuff out of his ass from the moment he wrote the Red Wedding. I'm genuinely open minded here.
R + L = J
I believe GRRM said that he was going to do a time jump after book three but had to write some synopsis of what happened to the characters during the jump. The synopsis became so much that he ended up just making them into books. He really hasn't written himself in a corner and I'm still expecting the predicted ending of the series.
Fwiw, I've read almost all his other novels by now, and mostly they have satisfying endings.