The Return Of LOST and Beyond

[Vincent, Thunder God]

I believe people die when they overcome something(s) Examples...

Boone-He got over his sister and gained self-confidence.
Eko-He realized a lot of his acts were not entirely wrong.
Shannon-She started to love others, and receive love in return.
Charlie-No more drug addiction and he starts to regain faith.
Ana Lucia-She had an open option to kill Henry/Ben like she's done in the past, but decides no too.
Libby-Don't know enough about her.

Just me, though.

That's a good point because it could be the Universe self-correcting, as the woman said in Desmond's vision, and as he said himself.

If they hadn't landed on the Island, none of those people would have come to their realizations, and to the transformations that would change their lives and fix all their problems, just like Desmond was trying to do but couldn't.