The reason for that is that no professional Content company has made content for "can cats eat asparagus" yet. If this ever pops up on SEMRush or SEOMoz people

The reason for that is that no professional Content company has made content for "can cats eat asparagus" yet. If this ever pops up on SEMRush or SEOMoz people will start making pages for it, and the results that don't get clicked will be driven to the second or third page.