True Story : I had been writing a book for about a year, at around 8 hours a day. I had over 2,000 pages completed, and plans/drafts for 3 more books, which would total almost 10,000 pages when fully completed.
I had 4 proof-readers that helped with things and they were all on board for the long haul. Nothing "bad" ever happened during the creation of this story. One day I woke up and said I needed a break.
The next day I enjoyed the break, and took another. For a week I didn't write anything, but kept drafting ideas. By the end of the week, I had to admit I was completely burnt out.
Two weeks later I hadn't touched it, and while I love the story, my proof-readers want more, and my drafts are still in boxes ... I just can't touch it. At all. It's been over half a year, and I just can't do it.
I like to think that's what happened with George RR Martin's Song of Ice and Fire. I assume that's what's happened to BrainDrop. But he can't admit it. Just like George.