Stack Exchange has the concept of a "Historical Lock", where a question and its answers are locked from edits or votes (and obviously no new answers can be added).
What is a historical lock, and what is it used for?
A historical lock preserves older content that was very popular when it was originally posted, but is now off-topic or otherwise out of scope for the site it is posted on. Historically locking a post ends the debate over whether a question should be kept on the site or deleted, and is often the final state of a question that has been deleted and undeleted more than once.
We don't have any delete/undelete wars here, probably because there's only a handful of people who can cast delete/undelete votes. So that aspect of its use doesn't really apply here.
I'm not opposed to historical locks here per se, but I can't think of any questions where I think a historical lock would be useful. "Idle curiosity" isn't sufficient; the question and its answers should have useful content, even if the question would be off-topic and closed if asked now. Even my popular (and off-topic when I asked it) question about alternatives for Google Reader isn't worthy of a historical lock, because Google Reader is long gone and people who were looking for alternatives have either given up on RSS altogether or have found an alternative.
Can you add some questions that you think would be good candidates for a historical lock to your question?
I would think, if we were going to "historically lock" any questions, we'd have a discussion about them here on Meta first.