"fresh" questions have 14 days to establish a quorum of 5 votes, but old questions have only 4 days for that, which I guess makes it more of moderators decision thing, than a community one.
Taking into account the understandable aversion of moderators to close voting by themselves, the question is should we even bother close voting old question, or does it just generates pointless noise?
First, I need to mention that the time period is determined by the views, not the age. Here's a quote from the meta:
Close votes age away harmlessly if the threshold is not reach after a number of days. If the question has at least 100 views, close votes will age away after 4 days; otherwise close votes will age away after 14 days. Each new close vote resets the timer, so all close votes must be at least 4 or 14 days old respectively before aging occurs.
However, I agree with your latter argument. The reason could be that there is no notification for mods about closures, and they barely go through the closure review queue. If you take a look at the Closure Review History, you'll notice that only 5 of the last 100 reviews are done by a mod.
So it's somehow harder for these questions to receive enough close votes or a moderator's attention if they are not on the front page.
Having said that, I still find some good close votes on old questions in the queue, even though those posts are old, that doesn't mean they should be closed. We get a lot of low quality new answers on old off-topic questions every week.
