If so, why not allow an expanded universe, or at least complete those sequels and prequels that RJ had talked of? There's definitely an audience for that, which doesn't care that the story has nothing to do with RJ except it is set in his world.

I think this book is a big dud. But I suspect that's because Harriet had to finish this as part of her contract, but had no real interest in coming up with new stuff to fill in the gaps, and the notes that were present weren't easy enough to parse to get much new info. So they just made a goddamn glossary. It is terrible, but I don't think there's any more milking to look forward to.