As goldPseudo pointed out, we recently clarified the criteria for closing sites:
If a public beta site does not produce consistently helpful content, and lacks the caretakers needed for flags and spam to get handled and our Be Nice policy to be upheld, it will be closed.
It's been a year since we did a site self-evaluation. I'd say that the site does produce helpful content, but not consistently. We've had difficulty with plagiarism and questions here are far too often unanswerable by random people on the internet. (See some of the recent questions and let me know if you disagree.) As a result, 17% or so of questions have no (upvoted or accepted) answer. This isn't a catastrophic situation, but it is concerning.
I would say that in a strict sense, Islam—Stack Exchange does not lack caretakers. the moderator team has shown considerable dedication to keeping the site clear of spam, handling flag, and upholding the Be Nice policy. But in the broader sense, this community has long struggled with a lack of non-moderator leadership when it comes to activities such as closing questions and deleting posts.
You raise an interesting possibility: shut the site down so that it may be restarted. Presumably, the purpose would be to improve one or both of the weaknesses I mention above. I am skeptical, however.
For one thing, this meta has laid a sound foundation for building a high-quality Q&A site for Islam. If you look at frequently-linked meta questions, you'll find guidelines that promote a level playing field for Muslims to share their knowledge with each other. Many of the principles have been tested by actual posts on the main site. A restart would mean recreating this corpus and there's no guarantee the result would be better or even much different.
For another, starting from scratch would very likely mean picking new moderators and raising up new high-reputation users. I don't see any reason to expect the results will be different a second time for this aspect of the site either. So I imagine if this site is closed, we will be in no hurry to restart the topic again.
I'm now going to step into somewhat speculative waters and suggest that power distance plays a large role in why non-moderators have been hesitant to take responsiblity for the quality of posts on this site:
[The Power Distance Index] expresses the degree to which the less powerful members of a society accept and expect that power is distributed unequally. The fundamental issue here is how a society handles inequalities among people. People in societies exhibiting a large degree of Power Distance accept a hierarchical order in which everybody has a place and which needs no further justification. In societies with low Power Distance, people strive to equalise the distribution of power and demand justification for inequalities of power.
The United States, where the Stack Exchange model was designed, has a fairly low power distance and values individualism. As a result, the organizing structure of the Stack Exchange network is strongly pluralistic. We expect people who have earned privileges to use them. And on most sites, we do see non-moderators step up to be leaders within the community.
Obviously attitudes differ from person to person, but countries with large Muslim populations (such as Morocco and Indonesia) tend to have high power distance combined with low individualism. In those cultures, people tend to defer to authority figures. In fact the primary division within Islam splits along the lines of accepted leadership.
Therefore, I believe that some of the difficulties Islam—Stack Exchange has stem from different cultural understandings. People who tend to think of the site as Islam—Stack Exchange are less likely to take personal ownership of the site than people who think of it as Islam—Stack Exchange. And broad, personal investment in a community is likely what's needed to make a Stack Exchange site work.
Ironically, posts like this one and firm moderator actions intended to steer users toward productive and away from unproductive actions tend to aggravate the problem. Far too often people have taken to questioning authority on this site by charging moderators with bias and asking me to depose them. That's really not getting use anywhere. I don't think either the moderators or the Community Team want to impose our will on other people.