I'm pretty sure one major reason Martin hasn't finished WINDS OF WINTER after over 10 years (never mind A DREAM OF SPRING) is that he he finds it easier to spaw

I'm pretty sure one major reason Martin hasn't finished WINDS OF WINTER after over 10 years (never mind A DREAM OF SPRING) is that he he finds it easier to spawn new characters and subplots than to wrap them up. I.e. the TV series looks bad compared to the books because they had to tackle the hard part and Martin hasn't yet shown he'll do better.