As harsh as it is to say this: Christopher Tolkien is 90. Eventually, the Tolkien estate will be headed by someone who is more interested in money and a Silmarillion TV series or film will become inevitable. Whether that will be a good or a bad thing, only time can tell.

EDIT: Weird thing I just learned - Chistopher's son, Michael George Tolkien, is just two years younger than Christopher's wife.