This question is brought to mind when I had a look at this (closed and deleted) question:
It also relates to my (closed) Meta question
and it's a serious question.
Back in the Old Days, questions that were more open-ended were considered fair game. Some interesting questions were asked. Some people put effort and the sum of years of experience into answers.
Years later, five people come by and vote to close because it doesn't fit the Q&A format. The someone who happens to have mod powers deletes it.
Now, oddly, these questions still accumulate upvotes -- I noticed the issue on the question linked when I picked up an upvote for an old answer and wanted to see what I'd said. They were clearly considered informative at the time, and since they do still accumulate upvotes they apparently still are considered informative.
Given this, I've got to wonder, exactly what is the utility of the whole process? It appears to have essential flaws.
The Five-Vote Threshold is Flawed
Unlike the early days, SO now has a user community certainly in the many hundreds of thousands, and a question collection in the many hundreds of thousands or millions. The probability that a particular old question would be visited randomly would naturally seem to be low; purely on that basis, the chances of an old question accumulating five close votes would also seem to be low.
However, informally, I notice that many times I see the same names in the close votes. I don't hae the time or interest to perform a social-network analysis, but I would bet cash money that if one were performed, we would observe a small group of people who spend a significant effort closing questions. Consider, as a gedankenexperiment, a group of 5 users who decided they want to close all questions asked by Canadians before 1 April 2010. They compose a search and start voting to close; how many questions would be closed before it was questioned?
The point is that whether or not my social-network hypothesis is currently true, the five-votes-to-close policy is vulnerable to exploitation by cliques.
The Current Process Has Little Beneficial Effect With Old Questions
Consider: a question that is closed can no longer be answered, but the question and answer are still visible, and answers can still be upvoted and downvoted. Thus, the questions still require database space, and still generate transactions. Thus, closing an old question would not seem to significantly change the use of (increasingly inexpensive) resources.
Compare that to a new question -- it may be repetitive, it may be unconstructive, it may be illegible or incomprehensible. Those questions will tend to quickly receive close votes, and appropriately; the reason, however, isn't primarily for computation resources, but for the community's time and effort. They either have been answered, or can't be usefully answered, and so should be out of the way.
This clearly doesn't apply to an older question that was asked, voted useful, and received upvoted and accepted answers.
Given that, it would appear that the effort expended on closing old questions has essentially no beneficial effect for the community.
Closing Old and Upvoted Questions is Inherently Abusive
Again, consider an old question with upvotes and accepted, popular answers. Both questions and answers represent effort and knowledge on the part of the writers. In my case (because this is, after all, about me) I get paid a lot of money to write about computer issues, answer people's questions, and explain things. I have also contributed a lot of those same skills and talents to SO for free -- as evidenced by the fact that I'm currently in the top 300 all time contributors in terms of reputation. When a question I've answered, especially with a longer, informative answer, is deleted, that has the absolutely inescapable effect of destroying my work.
And in fact, it's not all about me: the same thing is happening to many other people. Each of them is having their work effectively denigrated at best and destroyed at worst.
The fact that it's contributed for free doesn't mean it has no value.
It's certainly unfair to simply complain without suggestions for ways the process could be improved. Here are a few.
1. Increase the number of votes required to close old questions
The current voting process is, as shown above, inherently flawed and vulnerable to cliques. By increasing the number of votes required to close a question as the question grows older, this vulnerability is at least reduced. (Not eliminated: in fact, the process has the same vulnerability with brand new questions -- a conspiratorial clique could, for example, decide to vote to close all questions from Egyptians as soon as asked. However, with newer questions, that at least would probably generate controversy quickly.)
2. Establish a threshold based on age and vote count beyond which questions cannot be deleted.
At some point, a question which is still accumulating upvotes long after it was originally asked has proven its utility. Such questions should be preserved; they clearly represent useful information, and as discussed above, the benefit of close/delete on older questions is itself unclear.
3. Establish a place to put these older questions
As I've said above, deleting questions with useful upvoted answers is itself inherently an abuse of members of the community. A lot of this abuse now seems to be happening based on a new understanding of what is or is not "constructive" -- many of these questions were more discursive, at a time when discursive, pedagogical answers were acceptable. The work of community members in answering these questions should not be discarded.
I notice that another person who's made similar complaints is Norman Ramsey. It's work noting that he's one of the more brilliant computer scientists in the world. Do we really want a policy that discourages people of that caliber from contributing?