The Survivors are "The Replacements"

I think that the plane crashed specifically because of Locke. He was destined to be the replacement, next to Desmond. Therefore, an entire plane had to go down just for one man, Locke, to get there, and replace Calvin. The rest of the survivors can then keep a continuous cycle of replacement until everyone's dead except for Aaron.

interesting theory, locke does seem to have prior knowledge of the hatch, there is a good chance its got something to do with him