Frank Darabont says George Lucas nixed his script:
[Spielberg] was ecstatic with the result and was ready to shoot it two years ago. He was very, very happy with the script and said it was the best draft of anything since Raiders of the Lost Ark. That’s really high praise and gave me a real sense of accomplishment, especially when you love the material you’re working on as much as I love the Indiana Jones films.
And then you have George Lucas read it and say, ‘Yeah, I don’t think so, I don’t like it.’ And then he resets it to zero when Spielberg is ready to shoot it that coming year, [which] is a real kick to the nuts. You can only waste so much time and so many years of your life on experiences like that, you can only get so emotionally invested and have the rug pulled out from under you before you say enough of that.