What does the ending of The Beach mean?

Danny Boyle was rather more down-to-Earth in his assessment of the ending:

Of course, there's also a touch of imperialism to the whole backpacker thing. And we tried to criticize that in the film. But the film doesn't really become about that, it becomes about Leo, and he was great, but that's what the film becomes about, when actually it's meant to be about the Thai farmer at the end who says, "f*ck off, you lot, leave here, leave us. We don't want you, you destroyed the place." That's what it was meant to be about.

He did offer some crumbs of comfort in this interview alongside the author of the source novel (Alex Garland) and the film's scriptwriter (John Hodge)

Q: Why did you mess with Alex's ending?

JH: It was too gruesome.

Q: Alex, defend your ending!

AG: I like very bloody, bleak, apocalyptic endings. It's interesting what Danny was saying about American audiences, because I don't think there is any redemption in the book. Maybe that's why it didn't engage there. I think the book and the film are completely different things, but the darker the film got, the more I enjoyed it. I like the idea that you're looking through someone's eyes who's got a more distorted vision than you have.

DB: I must say, I thought our ending was superior to the book. It's an amazing book, a modern parable, but 1 think it did depend on this Lord of the Flies denouement, this terrible primitivism . . . but this is quite a sophisticated society they build up. Everything that happens, it's because they can't help creating rules and plans—it's not a return to nature at all. So I think John took ingredients of Alex's story and completed them in a better way.

Q: I did think that Richard's descent into madness was a problem. In the book, it's easier, because we're inside his head, but it seems very sudden in the film.

DB: Yeah, it does. We had an earlier version, which was more than two and a half hours long, which had more of the community, and more of that. It's not signposted, except that for me what it's about is a group of people who cut themselves off. They're a microcosm of us, because we'd all like to cut ourselves off and live in paradise, and he becomes a kind of microcosm of them. He becomes an island, a secret. He chases happiness, but for him contentment is not enough. Contentment is available on the beach, but is has to be more intense for Richard. It's a modern disease, and in a curious way it's linked to detachment, the idea that somewhere there's something more intense. That's his madness.

AC: And he doesn't start out a blank slate, he's not completely sane and balanced. He's explicitly hungry, seeking this out . ..