This would answer my question, if only it had a real, accepted, useful answer, which is why I ask.
I understand why this has happened. Indeed, there are plenty closey votes on the old Q, and it's probably for the best, but I wonder if we have a policy on this.
I don't intend to challenge Mego or the close-voters by asking this question here. I intend to understand more clearly under which circumstances this sort of retro duplicate identification is good or common.
This question pair I cite in particular does have a discussion, which is helpful to me, but I want to know about the broader scope of all questions, not only a restrictions-differences-semantics centered discussion.
When is it appropriate to close an old question of a dupe as a newer one?
I don't believe the two questions are duplicates really, because I think that their separation of intent and time is enough. (This is not reflected by my vote to close, which I cast when I had a different opinion about this 20 minutes ago.)