book vs film vs TV series

Just thought about the criticisms Prometheus has been getting re the script, content and storyline. Most novels including SciFi books are standalone - not all I admit Books can spend a long and detailed time building characters and mini story lines. If you try to make a film of a 500 page novel surely there is so much you have to leave out, deciding what would be difficult to say the least. Prometheus is not a book (yet) but it could be a splendid one and could easily go way beyond the film ending. The creation of TV Series (eg Twilight, True Blood,Sarah Connor Chronicles) is a different challenge. The writers and producers have the ability to change things (moods/characters) on the fly and take a longer approach to developing the storyline. I still contend that you couldn't fit any more stuff into a 2 hour Prometheus. Now a 3 hour epic would have been a different matter - but Fox and most other film companies will not give directors that leeway nowadays. Shame really because I could have sat through another hour easily and I think it would have produced a more satisfying result - still loved it though!