I want to ask why this question isn't closed even though the user has not shown any work. I flagged this post 10 days before but still no action. Why is it so? I know many such question have been asked before but I want to know specifically why this post is not closed?
The short is that nobody looked at the post (or maybe somebody looked but nobody took action). Why exactly this was the case is impossible to know.
The longer version.
First, to be clear, you did take the correct action, which was that you raised a "close" flag. This is the equivalent of voting to close for users that do not yet have that privilege. (By contrast, it would not be appropriate to raise a flag for moderation intervention.)
This action puts the question in the close review queue. There other users (not moderators) are asked to express their opinion. They can either add a vote to close, or vote that it should not be closed.
In the specific case neither happened for ten days. This is unusual. It's impossible to know why exactly it happened. But here are a few points.
There is a backlog of posts, because too few users review. Thus, some delay is expected but not that long.
The question only had rare tags and thus low visibility. Various users filter by tags.
The subject is a bit advanced. Some reviewers might not have felt comfortable to vote because of this.
Now what to do in such a case?
Beyond the obvious and non-satisfying to simply wait an option is what was already mentioned in a comment, namely to post in the chatroom CURED about the post. In this room various active users coordinate reviewing of posts.
You can go there, post a link to the question and say that you flagged to close it but the flag is still pending. But only do this after a reasonable waiting-period of a few days at least. In the current case it would have been appropriate. But do not do this right away or as a substitute for raising the flag to close.
In principle there are other ways to get more attention, like posting to meta or raising flags for moderator attention, but this is in general discouraged if the goal is merely to get a post closed.