This is correct; answerable questions tend to get answers. Low quality questions tend to still get answers, but often of lesser significance to the OP's needs. And if we could guess better the significance would improve, but that's the problem -- sometimes we cannot guess our way through poorly specified questions.

Those that get no answer at all are usually of such irrelevance, or so extremely specific that they never could or should. I get the sense that unanswered but answerable questions are so rare that it wouldn't be worth much effort tracking them down, especially after enough time has passed that nobody's looking at them anymore.

We don't have a "mark this question as answered" feature, so it is impossible to be sure that a thread with answers actually hit the mark unless the OP let's us know, which is usually not the case and not generally encouraged.