The title says it all. All questions should have at least one answer IMO.
What to do with unanswered questions?
Should they be brought back to the top of the list to get more attention? Bounties?
I did consider leaving this unanswered, but that may be too meta even for here.
I would:
Try answer them, a bit of base knowledge plus google-fu goes a long way sometimes.
Boost them to the top.
Add bounties.
Ensure they make sense, are not duplicates etc.....
And are we talking no one has provided an answer or no-one has accepted an answer. I am guessing provided as we seem to have many many where people have not accepted any put forward.