Everyone thinks the h-bomb might mean reset. noooooooooooooooooo way!
Ben turning the wheel was a reset if you ask me. All the places we flashed to after that were then written into the timeline. Look at that, many of them are quite similar - course correction. But then some things did seem different didnt they.
And what about the time in between the jumps? THAT is the tabula rasa.
So everything that happenes happens, but if you blank something out not only will it course correct, you can tweak with it. add things here and there. first loop jacob brought black rock to try and stop the end from happening. didnt work, so next time he tried danielle maybe, failed again. next loop hanry gale, NO wtf?! How about desmond, bah!! 815, will it finally work!?!? but every time now they all have to come, one way or another.
we know the key events the universe will correct to.
so locke turns the wheel which stops the flashing and resetting of chunks of time. The chunks we witnessed are WHH and everything between, in the tabula rasa, will course correct to make sure it happens. they get dropped off in 1977. Between then and the closest future flash we saw its all tabula rasa. but whatever happens must ensure those pieces of freshly written time.
i bet i could have said that better.