I worry far too much that not replying when others reply to me will make them think I deliberately snubbed them. Unfortunately, that can result in an infinite loop (particularly if I make that position clear and OTHER people think I get the same impression when THEY do not reply.) In this case, I undoubtedly should have just NBed, as Isaac pointed out, but I did not think of that at the time, but I could easily see that thread resuming indefinitely had it not been locked.

As to your larger points in the subthreads, I am obliged to say I agree wholeheartedly with all of them: If the discussion is truly dead rather than merely slumbering, no heroic efforts will restore it to life and there is thus no need to lock the thread; if it DOES retain some life reinvigorated by renewed attention, locking the thread preempts a resumed conversation in which there was manifestly wide interest. Maybe a year and a half is pushing it, but it is the internet: We can expect new arrivals at any time who may have something to contribute to a past discussion, and, with a literary site especially, it is quite likely a new perspective on an old novel could spark a lively and worthwhile new discussion. Likewise, new perspectives on old analyses could generate thought provoking and interesting discussion of them, or provide fresh stimulus to a discussion that ended less because it was concluded than because it had simply grown stale. In the days when I frequented Planet Tolkien I DID have a habit of "necroing" threads on various sections of the Silmarillion when I stumbled upon a year old discussion of a favorite section and noticed several (IMHO) key points had been overlooked, or discovered perspectives on it that I had previously not considered.

Perhaps it is only the law of averages (or vanity,) but I suspect I have had more locked threads than anyone AND more questions WHY the thread was locked. Maybe I am overestimating myself or others, but I cannot help thinking that a Rules and/or Help section stating the types of things that lead to threadlocking might result in less locked threads, or at least less questions about why they were locked. It certainly would not hurt.