Duplication is orthogonal to the current status of the target question. If a question is off-topic or too broad or something else close-worthy, then asking it again doesn't make it less off-topic or too broad or whatever. If they're duplicates, they should be marked as duplicates -- ideally before the newer question accumulates answers.
Questions that are on hold or closed can potentially be fixed and reopened. But if they're not they can still provide value as signposts; that's why we don't automatically delete all closed questions and duplicates. If somebody starts to ask a question that would be closed, we want a match to pop up so he'll go look at that and see that it was closed. It stinks to put in a lot of effort asking a question only to find out it couldn't have worked; if he finds it via search before writing it up, that's a win.
As for the current pair of questions, I haven't reviewed the answers, but in special cases moderators can merge questions to bring good answers together on one question. It's all-or-nothing; we can't just migrate some answers. I see several zero-score answers and a couple upvoted ones; I don't know if that's worth a merge. If somebody wants to make a pitch for it, we'll consider it.
All that said, I'm not convinced they're duplicates. One asks about the ramifications of making this kind of recommendation; the other asks how to do it.