Lots of chaff to sift through, things in wrong categories, and sizing widely varying between sellers / continents. (cici-marie.com)
I've seen ebooks in wrong categories, and some even skip the subcategories. (authoru.org)
It could be that you're targeting the wrong category of users, that your market is changing or a new unsupported use case is developing that your product is primed to serve. (entrepreneur.com)