I'd guess that it has something to do with being an ongoing story with no set posting schedule or part numbers. A lot of people hesitate to get invested in stories like that, because they're so often abandoned mid-way through! Also, some people wait for the end of a multi-part series, and then leave feedback for the whole thing. When you posted the first bit, it wasn't clear that there would be more, so people were leaving feedback for a finished story. Following parts make it into a WIP, and folks, as I said, will definitely leave less feedback for those, in my experience.
no subject