We've already discussed this in the chat and my take on the issue is that
- it isn't really clear whether "duplicate" means "duplicate question" or "duplicate answer",
- I don't like having many identical answers to what's essentially the same question, and
- I'm fine with having many different questions that are linked to the same answers.
There's a whole category of problems users run into which, although they arise from the same cause, and thus warrant the same answer, don't result in the same question, since formulating this question would require understanding the cause of the problem. The (in)famous "Why is the result of i = ++i + i++ not blah?" in the c++ tag is one of these. Once it's understood, it's easy to formulate the right question ("Isn't there a sequence point between the operands of +?), but since whoever runs into this doesn't understand it, this will be asked again and again.
I really see no point in answering these questions over and over. One important reason is that the answers come in widely varying degrees of completeness, clarity, and comprehensiveness. It's much better for the community to put its effort into creating one or two very good answers. I think it would be much better to link all such questions of one category to a (set of) very good answer(s).
es, often it would be good to keep the questions around, pointing to this one good answer.
So for me the problem is with questions getting deleted after they got closed as dupes. Deleting a duplicate if OK if the question was already asked (almost) literally. Deleting a question that got closed as a dupe is not OK if the question warrants the same answer, even though whoever asked it didn't know this.