GW isn't going to kill it off anytime soon. It is their third core game and they even recently penned a new contract granting them access to some of the stories from the Simirillion as well as the Unfinished tales. Additionally, they are still regularly releasing new miniatures, new boxed sets and new rules for the system. Despite Kirby & Co's repeated bleatings that the LotR bubble is the cause of all their financial woes, their actions (namely the aforementioned, as well as keeping their best sculptors and artists working on new LotR product) directly contradict any suggestions that LotR will be dumped anytime soon.
Sorry. It just ain't gonna happen. It'd be stupid to happen too, as LotR is probably what has been keeping GW afloat. Keep in mind that the Tolkien/LotR fanbase is much, much larger than the wargaming fan base and full of people who don't traditionally "wargame" and will be just as happy to glue the figures together and play without even thinking to paint them up. LotR is also being sold through vastly wider retail channels (ie: big mainstream stores like Barnes & Noble and similar) than the remainder of their products. Lastly, GW has put plenty of material from existing WHFB and 40k products online, yet nobody has ever suggested either of those game systems are going the way of the dodo.