"I don't know, but that's a very good question."
You start with statement. You end with statement. This (I presume) sums up the persona's life. He is confused still, despite living all these years, and all he can do is assessing the goodness of the question, which does not help him in anyway. He's lost and helpless, and perhaps he said ''that's a very good question'' to coax over this feeling of OMG he IS lost and helpless because he does not want to destroy this image of the great accomplished lucky young man that he's living in. He doesn't want to see the real world as we see him, though he's " slowly but surely" realizing the truth.
"detached from his surroundings" puts more emphasis to how alienated he is from real life, because his current life is like the silhouette of the lady, "blurry, but satisfying".
~ Great work !