I created a non-commercial link site recently. The main competition's site ranking had been off the 1st SERPS page prior to my creating my link (directory) site and has since dropped further. I'm hoping my effort was the cause!
There are only two established 'authority' directory sites in this niche that's a sub-niche of a larger sector. The linked to site is small beans by WW standards; a few thousand views and less than $50k USD 'net' per year.
The first 'authority' directory site no longer takes new links nor responds to their form's email requests. The second has the links wrapped in a double link condom that makes a nofollow link seem juicy :-)
If there were more than two 'authority' directory sites I would have just persued link requests but felt the smallness of the niche justified the effort creating and linking such a site.