I begin to wonder if we (the community) really found the best plan or if we are reading a sadder ending.

I still wonder about that too. I assume Harry is still bound by the Unbreakable Vow. He's partially an Artificial General Intelligence, with the programmed portion being so obviously and clearly safe. He's the perfect means for EY to make a pedagogical point about the non obvious but potentially cataclysmic dangers of AGI.

I would think that he would consider making that point a worthwhile use of all the time he has spent on the book, whereas other points might not seem quite so worthwhile in comparison, to him.