Scrolling down the ell feed, one can see that the majority of questions do not have accepted answers. StackExchange as a website has a strong emphasis on accepting a useful and/or correct answer and I feel new users should be reminded (either by the system or other users) that they generally have to accept an answer if they found it useful.
I see this issue has been raised a couple of years ago here but it doesn't look like anything has changed. This is obviously a problem across all of StackExchange, but it seems particularly bad here.
Accepting answers incentivises answerers to keep answering questions, so what can we do about this?