Speculation about the state of the DI village in what we assume is the present lead to this comment in a community blog:
Flickmybic:"1. were the dharma signs shown in the barracks a production error? 20 years after the purge, there was no longer a need for those signs and i do not recall seeing such props in post-purge episodes before."
I think THIS is the big reveal of the episode, and almost nobody is talking about it. Those signs are there because the timeline has been altered somehow. It seems that the purge has never happened. There are a lot of differences at the barracks now: signs, boarded up windows, tons of overgrowth, and the "class photos" still being up in the rec room. All this indicates that the hostiles never took over the camp in this new/altered timeline. Which of course, goes against what Daniel said. Either he was wrong, or he was lying.
The thing is, we KNOW that history can change for some period of time. You CAN save someone that is going to die, but they will face death again the next day. But you can save them that day too... history keeps trying to repeat, but you can put it off, and the point is, you can do so inevitably.
In such a situation we cannot know which events we have seen were supposed to happen, or were a part of people continually manipulating history to keep what's supposed to happen from happening. Therefore, it's possible for someone to say, go back in time, and change things back to the way they were supposed to be. Perhaps the DI is never purged, perhaps it was not supposed to. Perhaps all the war on earth is the result of the wrong side winning Widmore's War in the first place, and now there is a chance to try again.
I don't know about all that, but I do know that if it's possible to divert history for N days... then we don't know which is destiny and which is perversion of destiny, and thus, which will lose out "in the end".