"As long as we interpret "successful" to mean as "it sounds good to me", aren’t we simply rationalizing our personal preferences? I don’t believe this is what Ellington had in mind."
Neither do I. And that is not the correct interpretation. I am sure he meant that ’Good Music’ crosses all musical, social, and cultural barriers or boundaries with it’s appeal, and as a minmum is considered among the best within it’s genre. I am sure he did not mean that ’Good Music’ was whatever he happened to like.
Cheers