I never understood Hollywood thinking in this respect, as a film of this genre, and subject matter will mostly appeal to people who want the whole thing, and are willing to sit for extended periods of time watching it...
... but they want it to appeal to the general masses, who only want a light show for an hour, so they cut it to ribbons, and it appeals to nobody.
And, as more recently, Christopher Nolan films have proved, if you let the filmmaker make the film for the audience he (or she) intends, and tailors it accordingly, others will be willing to give it a go.
(After all, they don't mind showing Ben Hur or Cleopatra every other bank holiday!).
mmarmmellaade: but if lynch'd been allowed to aim for a film half as long again (c. 190 mins instead of ~135), and shoot enough extra explanatory expansion to take an "producer's cut" up to two full dvds...
- fans'd've delighted in it more, and for longer, - but would it have been any more coherent?
This is what happens when a director bites off more than he can chew... a good cult film, mainly for it's short comings (oooh that kid is annoying!) but it was doomed from the off, as the book is a huge sci-fi epic, which goes deeper into ecology, religion, and politics than could have been found space for in a movie, so a lot of it was lost in translation.
I believe there was a TV series (Mini-series) which attempted to address this problem, and expand into the other book in the series, but I haven't personally seen them.