This is a common concern with the community: Why are certain questions closed as duplicates of others when they ask for different things. It's simple: The answer to both questions lead to the same answer.
But wait... the question is closed as a duplicate of another question, which is completely wrong when the questions don't ask for the same thing. Right? Correct. But also not really. I'll try to explain.
In some instances the question asked may be different from another "duplicate", but *the linked answers best answered the OP's question, or was the most helpful in finding the solution" (taken from the tooltip text when accepting an answer). Viewed differently, consider the following two outrageous questions:
How do I keep the rain off my back?
How do I stay warm at night?
The questions are obviously different. However, if Question 1 was solved by the answer "Build a house." and the poster of Question 2 felt that such an answer also solved their problem, there's no use in duplicating the answer? If the post is marked as a "duplicate", any visitor to question 1 will see the marked duplicate and find an answer.
Okay, but what if the answer doesn't solve the problem to Questioner 3? Well then, they ask a new question with a reference to Question 1 and/or 2 with reasons why the answer didn't solve their problem - we've seen those questions pop up every now-and-again.
I think inherently the problem might just be with the wording of our responses for closures:
We are limited by these. We sometimes close questions as being off-topic because they are minor, yet the question is clearly on-topic (previously this would have been better filed as a "too localized" closure, but we don't have that option anymore). We sometimes close questions that aren't reproducible as being unclear when it's perfectly clear that the OP has a problem.
In closing, there are no hard-and-fast rules in terms of community decisions. Some people make decisions for the greater good. Other people make decisions out of personal gain/interest.