[manasecret]

So this explains a lot.

Faraday explained to Kate and Jack how to make everything not happen like it did, namely blow up the hydrogen bomb. Faraday may be dead now, but the important information he had and his notebook still lives.

If the plane never crashes on the island, it changes everything. Really think about it.

1. The plane never crashes, all the survivors and the non-survivors on the plane never crash - so they're all "saved".
2. The survivors never reach the Dharma Initiative, which means Ben would never have been shot, and he never would have joined the Others.
3. Without Ben joining the Others, he never becomes their leader and Charles Whitmore never gets banished. Thus, the entirety of Ben's plotting and killings would never happen.
4. Presumably, if Charles Whitmore remains the Others' leader, then Daniel Faraday and his mom would both still be on the island. Daniel would then never get shot by his mom.

This gives reason for why Whitmore wants to help all the Survivors stay alive and why Ben is so willing to kill them off when he thinks he can. Presumably, Whitmore, and perhaps Ben, know what happens if the survivors get back to the island - i.e. Faraday's knowledge stops everything which means Whitmore would have never left the island and Ben would never have joined the others. Good for Whitmore, bad for Ben.

It also explains why Faraday's mom was so willing to spend her whole life raising her only son to go to island even though she knew she would shoot him. She knew that the only chance for her to save her son from her was to send him back so he could stop the whole chain of events from happening in the very beginning.

Taking that reasoning, it also explains why Ben wants back to the island -- so he can stop the survivors from stopping everything. However, it seems he didn't know about the survivors in the Dharma Initiative, so that explanation of Ben's reasoning doesn't quite work.

So the question is, will the survivors actually be able to become "the variable" and stop everything from where it started?

If so, it's pretty much just one super-fancy way of the writers' saying "Hey, you know all that stuff you just watched for the past six years?? Just kidding!!" In which case, I will break my TV.