I think the most recent Lego Catalogue is a clear indication of success for the Middle Earth lines. I am certainly not saying that they did not sell, however we do not know details such as how much it cost TLC to procure the rights to do the lines. They may have paid a premium hoping that the 2 (at the time) Hobbit movies would be as big as the LotR movies and even with a 3rd movie that seems unlikely to happen.
I wonder if it would be worth something to an online store to purchase the rights to make specific molds and sets as well. Lego is not the only company out there and it appears at a cursory glance online that there are quite a few LotR Lego collectors.
Speaking of other companies, I wonder if one of the bigger competitors like Kree-O would jump on this line after? Perhaps market it as a Middle Earth line to avoid seperation of the movies and bring sone of the sets that were missed?