On the one hand, I can see where you are coming from. Wanting to know the status of a WIP for sure is reasonable and understandable.
On the other, an author may not know of the… investment their audience has in their work, and may simply never think that this is something their audience wants. They might not even want to publish a WIP if authors are told they have to keep this in mind because of the implicit pressure of knowing audience expectations beforehand. Or they might know, but don’t want to risk disappointing their fans by telling them they can’t maintain the WIP. Maybe they are having mental health struggles, or perhaps they physically can’t post anymore.
It isn’t just a matter of honesty. There are serious contextual factors that need to be considered, especially before we make any judgements about the authors. And, regardless of whether it is a disappointment that a WIP receives no news, I am truly of the opinion that this being something authors opt into is the best way for WIP threads and everyone involved to be treated.
Edit: Sorry if that was overly dramatic or anything. I just believe that if this is truly a serious discussion, we need to evaluate it from multiple sides rather than simplifying it as people (not anyone specifically, in general) tend to.