>>213872087
I don't think this is the case, what I think is that Martin aged, and as he aged the thematic problems with the story became irreconcilable.
Consider that when Martin started this he was, if not young, at least closer to birth than to death, closer to the vital energy of rebellion that possessed him when he was young. Writing a subversion of all fantasy mytho-poetic tropes made sense, he was sticking it to the man, as it were, by creating a story which defied the morality, the idealism, the romanticism of older works.
Nobility is false, all knights are either bastards or fools. The gods are false or evil, there is no divine providence, only doom, ruthlessness and power are the triumphant qualities in man, etc etc etc blah blah blah. Great you have what amounts to violent medieval soul-pornography, but what happens when you get older, and you're graying and nearing the end of your life, and THIS is the only thing you have to show for it?
The monument he has chosen to make for his life is one that essentially screams nihilism and despair. And now rather than a young cynic attacking the foundation of his oppressors, HE is one of the elderly, and the roots that have been cloven are supposed to feed his soul, give him hope and solance.
He cannot finish the book because to finish it would be to face the fact that he spent his entire life subverting beauty and hope, and as he grows old, he has realized that beauty and hope are the only things that can bring peace to an old man. He is tired of being bitter and exhausted, tired of being spiteful and degenerate, and he cannot fix what he has done--he can only stop, stop and cause no more damage.