I knew my Kong reference would throw some people.
What I meant by that is that most of the films you mentioned were "event" movies...films built up by their creators and expected to be "worthy", epic blockbusters. They were either based on big books (Godfather) or had serious Academy aspirations (Ten Commandments, Lawrence, Titanic) or both (Gone With The Wind).
Even the Lord Of The Rings films, being based on "important" literature, were seen as being long but understandably epic length...there was no complaining that these films <I>shouldn't</I> be these lengths.
The win for Best Pic on Return Of The King <I>did</I> validate that those kinds of fantasy films could be "worthy" as well, but really that win gave Jackson the clout to make his King Kong whatever length he wanted.
Now, Kong is a popcorn movie...nothing more and certainly nothing less. Popcorn movies used to be 90 minutes or so, but they've crept up to being roughly 2 hours. Most good, decent blockbuster pictures - those that win technical awards but little else - your science fiction, comic book, adventure movies - are all around the 2 hour mark.
What Kong did that nothing else had done before was to say "hey, why can't a summer blockbuster popcorn movie be epic length?"
Yes, I know Kong came out at year's end, but the point is that the film singlehandedly sustained the attention, built up credible characters, not least Kong himself, and suggested that, if the elements were in place, a well-made popcorn movie could hold and work at three hours-plus.
Kong never set out to snag a Best Picture. It's a monster movie. If it HAD won Best Picture or been nominated, it would have been down to the fact that it was a great film, pure and simple (not saying it is, but that's what would have gotten the support).
So, my point is that Kong, which was conceived and presented as a classic monster, audience driven piece of escapist entertainment, like nothing of that length had been before.
Made purely for fun.
No truly world-changing epic themes, no true-story backdrops, no weight on its shoulders from being adapted from a popular book. Just a fantasisc "ride film". And it worked at three and a quarter hours.
Now the doors are open for filmmakers to expand on that fairly self-imposed 2 hour/2.5 hour (also prefered by the exhibitors who like to get an extra show in). Raimi has a mega-anticipated and successful franchise from which he's springboarding, which helps no end. He knows this is going to get two or three prints into every multiplex, so he has the amount of showings covered.
The question is now - post King Kong - whether we're going to get a huge amount of director indulgence, or indeed if we're seeing a new format: the epic, special effects, comic book popcorn movie...