That's most likely the case. Fame has kind of spoiled GRRM. Although being ambitious with all the stories he wants to tell, he just doesn't have the discipline to follow through anymore. At the end of the day though, it's his life to live and he should be able to do what makes him happy, I suppose.
On a separate note...I'll say that my interest in the remaining A Song of Ice and Fire books dropped significantly once Roy Dotrice died. I just can't imagine the series without his voice narrating the books.