Jamon, what an excellent and relevant blog! … I was just reading about this a couple of months ago and discovered that these games / apps / music in the long tail end are coined “Zombie apps”. There is a great article supporting your research from TechCrunch: http://techcrunch.com/2015/01/30/zombie-apps-on-the-rise-83-of-apps-not-on-top-lists-up-from-74-last-year/
Although specific to Apps I can venture a guess that it is also relevant to other topics such as games in Valve or Music in either Itunes or Spotify.
The proposal / solution that you make is quite interesting but I would argue that it’s the developers responsibility of promoting and pushing their own content. It might be a bit cynical, but there might be a reason why Zombie apps stay as Zombie apps. (i.e. not great content, glitchy, poor performance, etc.) other than being unable to discover them.