Things Change by Scott Gingold

Daniel Faraday changed things. He prevented the purge. He did this in "The Other Woman" when he and Charlotte went to the Tempest station and he rendered the poison gas inert. They layed the ground rules for island time shifting early on in the fifth season when the Zodiac raft time shifted along with the Losties. Apparently if you move or change an object just prior to the time shift it shifts along with you. When Daniel altered the poison gas, the gas time shift along with Daniel and company back to the 70s, so when Ben tries to use it in the 80s during the purge, it no longer works. That was Daniel's intention all along, to prevent the purge.

There's been lots of discussion about an Alt Timeline vs. Whatever Happened Happened, but I think those two camps of people are missing the point. The show is using a mix of those two concepts, not separating them. This was made pretty clear in the third season during the whole "Charlie is gonna die" subplot. Desmond prevented Charlie's death four separate times before Charlie eventually accepted his fate in the Looking Glass Station. He was destined to die, and he always did die, so WHH. But at the same time, Desmond changed things, he did save Charlie's life 4 times, but the universe course corrected things. When Desmond saved Charlie the first time, the universe made sure there was another situation in which Charlie would die. So did Charlie drown trying to save Claire, fall on rocks, get struck by lightning and get struck with an arrow? Yes he did? But he also survived them and eventually drowned in the Looking Glass. These things all happened, but Desmond chan! ged them. This doesn't mean there's an ALT universe, or even an ALT timeline, it just means that the present time line was course corrected, with minor changes, but the overall big picture still always happens.

So how does this apply to Jughead and the incident? Well it's very possible that the incident does create a situation in which 815 never crashes, but then Ben, Widmore or possibly Jacob intervene and create the situation in which 815 does crash, course correcting events so what we've seen in the past 5 seasons always happened. This would explain all the coincidences and connections between the Losties. The repeating characters in different flashbacks were people sent to make sure the Losties stayed on their paths, so that when the after effects of the incident prevents 815 from crashing, they have to make sure that certain events happen so that time is course corrected and 815 does crash anyway. Just like Charlie died from taking an arrow to the neck, but then that was course corrected to him dying in the Looking Glass.

So is Desmond special? Sure, so is everybody who time travels, because now they all have the ability to change things, even though what they change will eventually be course corrected. The overall outcome will be the same, but the individual circumstances will be different.