I was thinking that many well known books have been made into high budget films (harry potter, Dune, Lord of the rings), yet the Discworld films so far have all been relatively low budget and simply shown on the TV. However some of the books seem to be very good for adapting to film (Lords and Ladies, Pyramids, Good Omens etc.) Yet few of the books have been made into films and none have been made into high budget films, does anybody know why?