I think this expectation is unfair to writers. It’s a big deal to declare a project dead rather than on hiatus; I bet most writers who’ve left their WIPs for a year or two (or even longer!) still hope to come back and finish them at some point. Most of them are mistaken in that hope, but not all – see Blood for Poppies. And for the few authors that might genuinely come back, it would be a shame if fans discouraged them by pushing for a hard yes-no after a few months of hiatus. If you can’t enjoy partial or unfinished work, or tolerate ambiguity over whether a work will be finished, don’t read WIPs.
Don’t get me wrong: there are WIPs I mourn too, and plenty of works in all media that I would have enjoyed more had they been finished (or finished properly, not in a rush). But calling creators rude or unfair for not formally killing off their dreams for our satisfaction is a level of entitlement I can’t support.