The only reason LotR is still so successful is because of the movies and the ensuing games/toys/etc. Try to get any teenager to read the books nowadays and they'll be asleep by page 10.
I got the impression that he would gladly forgo the money and new found popularity of his father's writings if it meant that Middle-Earth hadn't been turned into "an action film for teenagers" as he put it in the interview. Tolkien was a philologist (of Old English, no less) -- that's not a field you go into because you have a great love of or desire for money and fame. From what I can gather, The Silmarillion, and its associated stories, was his chief interest and passion, but no one was willing to publish something that demands a background in the epic poetry of dead Classical and Medieval languages in order to be fully appreciated and understood. Hence, the Hobbit, and subsequently, and due to continued publisher resistance to The Silmarillion, The Lord of the Rings. One of Tolkien's first publications was a volume of poetry called Songs for the Philologists -- the title should make clear whom he envisioned as the audience for his fictional work. As such, I think it's a mistake to think that Tolkien's aim was the creation of a commercial product to generate a profit and everflowing revenue stream for himself and his heirs. Rather, it was the creation of a prose epic that would appeal to those who know Homer and Beowulf well (and hopefully in Greek and Old English) and that would give to England a legendary and mythical alternate history, in the style of the Norse and Ancient Greeks, that would be distinctly English. With that in mind, I can see why Christopher Tolkien is a bit dismayed that Middle-Earth is now chiefly associated with some entertaining, but loud, bombastic, and utterly unsubtle films from a director of great visual imagination but little story telling talent.