I'm surprised to see that on this issue everybody is speaking of rep and nobody of the fundamental Goal of SO (or so it seems to me) : ask questions and give answers.
Closing not only has a negative effect on Questioners (they won't get answers), it also have a negative effect on people that answer.
Standards are very variables between users, some seems to vote to close any questions they even slightly dislike, or even downvote people based on low acceptation rate an previous history. It is a system bias that should be expected, because the close policy is de facto decided by the less tolerant people, with the lower rejection level. And not wanting to close a question is not the same as wanting to reopen it, no confusion here.
What is very disappointing for me is starting to work on a detailed answer to some question, trying to set up context to explain things, and finally find out that I can't post my answer because some other people decided to close the questions after 5 minutes. What is even worse is when this question is closed for being impossible to answer or too vague... of dear, nice to learn I was doing something impossible. And Indeed, now it is impossible to answer to the question. Not because of the question itself but because it was closed... (basically because some other peoples decided I shouldn't answer to that question).
Every times it happens I wonder if I should start again to write a detailed answer on anything, as there is a risk to just be loosing my time.
Another thing that bother me is that I'm just one year old on SO, but I notice a trend on lowering closing standards, closing more questions and faster.
But probably rep cost is indeed not a good way to manage closing policy. Other ways could be possible. Maybe something like allowing users with a given amount of rep, and if questions have not already too much answers (I perfectly understand that questions that allready have 100 answers should probably not get more) say less than ten, answers should be added even for closed questions. I believe that would totally void the problem with people forbidding others to answer some questions because they have lower standards.