How the Alt timeline fits in by LostJimmy

I've been trying to think how the ALT timeline is relevant to the show. I concede that it could be as simple as what many people are saying - it will end up being the end of the show (i.e. the alt timeline is the epilogue to the show). I kind of hope it wont be though, it seems a bit too obvious and I'd be disappointed with it.

My theory, which I thought I better post soon as it will probably be proven or disproven in the next few episodes, is along the lines of that when the bomb was detonated/not detonated by Juliet it created a Schrodingers cat situation of there being both possibilities simultaneously in play and that maybe on the island the local reality is that the bomb didnt go off, but outside of the island the reality for the rest of the world is that it did. I.e. both realities exist but in the same universe not in a parallel universe. So everyone who is on the island is experiencing the reality where the bomb didnt go off, but the rest of the world is now experiencing the reality where it did. So rather than being an alt timeline (which the producers I believe have said it isnt) and a main timeline, its more a case that there is one reality on the island and another off island.

As an extension of this, it would mean that everyone who is on the island now has an off island counterpart co-existing. Two versions of each of those characters currently exist in the Lost world. Damon and Carlton have said several times now something along the lines of that there are characters dead in the island timeline and alive in the off island timeline, but have posed the question 'what will happen if a character dies in the off island timeline?'

I'm wondering if each character has to die in one timeline or another so that only one version of them remains overall. So some characters will die on the island, and the others will die in the 'alt'. Maybe all but the final candidate will die on island, and he/she will die in the alt (to remain on the island in Jacob's role).

As I said, I think this theory will be proven or more likely disproven fairly quickly now that someone (Widmore) has come to the island from the outside. I am very intrigued by what will happen when someone dies in the alt timeline though, following what Damon/Carlton said. I was expecting that the alt Ben would die in the most recent episode (I thought they were being clever with the 'Ben will face his demise' promo) and we'd find out.