Memento and an Off-Island Ending by The Fool

Sorry if this has already been posted before. I was just reading what the previous theory posted was about and was reminded of the river comparison that Faraday used (or was deleted from the episode, I think). A large enough stone can fork the river in two directions for a while but they will eventually come back together and meet behind the stone. Applying this to Lost, this doesn't necessarily mean one timeline or the other will get erased.

If anyone has watched the film "Memento" you will see what I'm saying (spoilers regarding the structure of the movie, not the plot). The movie follows two separate timelines. One is a black-and-white flashback told in chronological order. The other is the present, told in color but in reverse chronological order. The movie alternates between scenes in the flashback and in the present, one moving forward, one moving backward.

At the end of the film, the two timelines meet. Before this, the last black-and-white scene shows what the character does before the final scene of the movie and the last color scene shows what the character does after the final scene. As for the final scene itself, it starts off as a black-and-white flashback but then fades to color as the two timelines cross each other.

As for how this is applied to Lost: One time line doesn't need to be wrong or erased as long as both are moving towards the same ending. Darlton might be using the flash sideways to show that, even if the Losties didn't crash on the island, their lives would ultimately end up at the same point, just with different specific events happening.

For example, suppose in episode 6.14 the on-island Losties have gotten off the island and decided to go the 2004 summer Olympics to stop Smokie. Now suppose the off-island, flash sideways Losties have ultimately come to the same conclusion: they must stop Smokie before he gets to the Olympics. One timeline shows how the characters get off the island and to the Olympics, the other simply shows them discovering each other and going to the Olympics. Either way, the ending is the same. It only ends once. Once the flash sideways characters and the regular characters end up in the same spot, trying to do the same thing, the timelines will come together and be told as the same story regardless of what happened before. This way, both timelines technically existed, but there will still only be one true ending. Course correction at its finest.

Of course, for this theory to be correct, it would require the on-island Losties to leave the island at some point during the series as the flash sideways characters can't get onto a sunken island. For the timelines to come together without being erased, the characters must be in nearly the exact same situation on both sides.

I'm not really sure I believe this theory, just throwing it out there. Take what you want from it. :)