It’s a shame, but perhaps by keeping these posts in front of as many eyeballs as possible for as long as possible might help the situation.
I've thought about this a lot. It's a challenge that goes deep, imo. In a way, cramming the book club paradigm into the SN (or HN, or Reddit, or ...) interaction model is a giant mismatch. The nature of engagement, and what is required of users, is just so different from the "here's an interesting link" model; and what it requires of an author to oversee such a thing is so different.
I think your territory curation provides some real inspiration for how this could be done better under the existing paradigm, but we can imagine an alternate universe, where the goal of SN was to make book clubs maximally awesome. What would it look like?
To be clear, I am absolutely not endorsing that SN should do that; but it's fun to think through what it would mean -- how would the front page look, would there even be a front page in the way we currently understand it, how would notifications work, etc. It seems super different, but really interesting to think through. Would be so fun to have the time to experiment with this, but alas.
Some similar energy to the question about evergreen-ness, it seems to me; and some of the recent discussion around how rewards work and how different flavors incentivize different stuff.