The short answer is that it’s too expensive for how much it’s generating.
The longer answer is that I think stackers, including myself, have a wide berth of interests, so the narrow topic of “movies” doesn’t fall within our general reading and posting habits. I think most of what gets posted in ~movies could probably have been posted in ~culture, or maybe, a more general ~entertainment. I could be wrong, and in the right hands, ~movies could kill it at the stacker box office.
I will leave that to a better stacker than me.