For traditional game engines it would be to many polygons, but it can be useful for some types of set creations for movie/video productions in general. Note that there are also different types of game productions where they use art creation workflows comparable to what matte painters do (use of pre rendered elements).
I think with your kind of service it may be good to get familiar with current workflows of these matte painters and see how your data could be beneficial to them (in generating 3D plates and background elements). Then work out a targeted marketing strategy (maybe make your point about the benefits in some showcase video) and then find out where to best place the news.
Placing the data on stock media websites is step one, but maybe these kind of artists are less familiar with this kind of data and so don't rely search for it on 3D stock media websites, so it's possible you may need to get attention/news out via some other means. Maybe place adds on some special websites best known by matte painters? (needs some research)
Also note, there are some evolutions in real-time game technology involving hybrid rendering systems (polygonal rendering in combination with voxel technology). With this kind of technologies it becomes possible to use your high poly meshes/textures as 3D brush stamps to paint in voxel terrains. You can find more info about these evolutions here (http://procworld.blogspot.be/) and see some examples here (http://voxelfarm.com/).
There are also all kinds of new opportunity's popping up for 3D scan data in VR experiences, see this example here, go to minute 9 to see a beautiful 3D scan of a world heritage site (https://www.youtube.com/watch?v=4o3uryy0ct4&feature=player_embedded).
Note that these kind of models are so optimized that you can run them on mobile phones and thus the mobile VR solutions (in photo real 3d).
Future will definitely present more opportunities/use cases for this kind of data, so I think you should definitely proceed on learning and doing the things you do and post about it in the right places, in time more feedback will guide you to the point where it all start to come together and pay off.
