Turned out the missing dates was a setting of the theme. Dates are back.
I wouldn’t mind if it showed the time, too, but dates are a bare minimum.
I’ve just noticed that this WordPress theme I’m using, Independent Publisher, doesn’t show dates and times of posts. And as a side effect it doesn’t have permalinks for posts without titles (the datestamp should be the permalink in that case).
How can this be? Has it always been like this and I just haven’t noticed? I hate sites that don’t have dates on posts.
One way or another, this will have to change.