The main problem with this that so the questions are left open indefinitely, only because of the untrustworthy behavior of the OP. On my opinion, questions should be allowed to left opened only if there is known that an answer exists, or it will maybe exist in the future, but nobody found it until now. But it is only my opinion, it seems the SE has other ideas and the always growing list of the undoned work somehow doesn't annoy them.
What can be done: doublecheck, if there is any of the possible close reasons. Destroying something can be done very efficiently here, in most cases it is enough if you flag it for close with any reason. It is especially okay, for example, if an essentially similar question, but with an accepted answer, appeared since the original opening - closing questions as duplicates is the most simple.