What Dennett meant is
Bob, I love your books, and I'm going to buy this one too, but your obsession with Dennett's so-called concession is getting increasingly embarassing. Here's what I think Dennett "meant":
1. Wright is not going to shut up about this question which he finds incredibly fascinating and I find totally uninteresting until one of us dies, which since I'm older, will probably be me, or he gets some sort of answer which satisfies him.
2. If I make appropriate wishy-washy, agreeable-sounding noises which don't actually constitute agreement, maybe that'll satisfy him and we can change the subject to something interesting.
I think if you roll the tape again, you'll find my take pretty convincing, especially if you really study the expression on Dennett's face as you keep pounding away; an expression which to me pretty clearly indicates that he'd actually stopped listening well before he make those agreeable-sounding noises.