I think there should not be any reason to delete closed questions just because they sound the same as another question.
If this is a technical stack exchange then yes I think duplicate questions with the same single answer can be deleted because in a sense the answers are just repeating.
But for the workplace, I think this is not applicable. A lot of people answer the same question, but there are instances that the answers are totally different and provide different views which to the OP and other readers and I think is beneficial for the whole network.
There are a lot of people providing good insights on how they would answer a question or what they think of the question. It would be a shame to just have them deleted because they appeared in a question that sounds like a previously asked question. Last time I checked, stackexchange provides answers, not delete them.