Closing duplicate is certainly a problem, as a variation in the way
the question is asked can suggest very different answers, and
sometimes much better ones.
If they are closed, the only alternative is to answer the old
question, which I know from experience is mostly a waste of time
because you start at the bottom of a list that is supposed to
order for quality and not for date. I hate writing for a black hole.
Another point is that duplicate policies are inconsistent, bordering
Now here, I will just copy a part of my answer to another question
about the quality of questions.
Regarding specifically the quality of questions, what matters most
is the sexyness-entertaining quality of the question, not actual
content or preparatory work. I will take the example of two questions
that are exactly on the same topic, but were not flagged as such:
Origin of motion and relative speed of bodies in the universe and
Why are there no asteroids or meteoroids with relativistic speeds?.
The first question was mine, actually my fist post on physics.SE after doing no physics for more decades than I care to tell. It took me a long time to write that question as I was trying to understand first what issues could matter, what kind of data and question might be sensible.
I was very lucky to be upvoted once, and to get a nice answer.
The second question was asked 2 month later. It is exactly the same issue, presented as a disaster movie. It was not detected as duplicate and attracted much attention and 20 upvotes.
So should I try to ask questions as a scientist, or as a showman ?
The other issue, directly related, is the questions removed as duplicate. First, it is inconsistant (see above) and sometimes inaccurate. Answering old questions is a waste of time. I know as I did it more than my share. Thoses answers do not get votes or comments, and I personnally hate writing for a black hole.
So the practice of stopping duplicate question is just the best way to ensure that further input will not come, of that a different perspective will be avoided. What would have happened if the second question above had been detected as duplicate, as it should have ?