Because it would only create more questions....."if everything did happen, but the plane lands in LA....then how did the plane blow up into pieces and crash on the island?"
In a word, Ka.
or in Lost speak, "course correction".
Ka differs from traditional thoughts on destiny because it is not “unalterable.” While ka might wish something to happen, it is not simply set to occur. If Roland (or anyone, for that matter) goes against what ka wishes to happen, then ka will alter how events play out until things go the way it wills, but there are no predetermined roles for people to play or how events will unfold.
From the essay linked above:
You see, the narrative arc in LOST must go from Point A to Point Z. There are a finite number of episodes in the series as determined by the execs at ABC and the creators. As of this writing, there are 18 more hours until Point Z airs and the series ends with either a bang or a whimper (or a “well, huh” like Battlestar Galactica did). Now, the Pilot episode is Point A. The series finale is Point Z. However, as the show progresses and the story evolves, there does not there have to exist a mere 24 points within the range of A to Z. And that’s where course correction comes in.
Since Charlie Pace’s death was integral to the narrative being completed as evidenced by the amount of course correction used to finally culminate it, then the event would exist as a static point in the series. For the sake of this example, let’s call it Point M. When Desmond prevented Charlie from dying to the electrical strike, Point M could no longer progress into Point N. The course correction, then, created a new narrative point that did not and could not have existed before: Point M1. The interesting part of this line of thought is that Point M1 cannot lead directly into Point N like the original plot would have. Events changed. And Desmond tried multiple times to prevent Charlie’s death, never allowing the narrative to reach Point N as was originally intended, so he repeatedly created various other Point M’s. Eventually, Point M4 (just as an example) was fulfilled and Charlie died. The narrative, however, still cannot go into Point N or even Point N1 because other “fated” events were changed, thus destroying the original narrative entirely.
Still following me? Okay.
So even though the original event never occurred, the intended outcome of the event eventually did—Charlie died. This led to even more course correction. Point M4 needed to get back on the original track because the fated outcome of the series is not the analogous Z4. It was simply Point Z. So Charlie’s death was not only impacted by the successive events, they were created by it, making the characters in LOST have experiences they were never intended to have, yet had to have in order to get linear time back on course. Point M4 would work toward getting back to Point Z through Point N4 then O3 then P2 and finally back to the original timeline of events with Point Q, but all of these corrected points diverge from the original timeline and exist only because fate and destiny on LOST are not unalterable.
The rescue, subsequent timejumps and seemingly safe arrival in LAX are just course corrections like Desmond trying to prevent Charlie's death. Point Z, I'm guessing resolves the age old conflict between Jacob and MiB but also sets into motion the chain of events that lead to Point A (as well as the Adam and Eve skeletons), looping the story back onto itself. Jack has continually tried to "fix" everything but he is beginning to learn, as Desmond did, that he cannot, and should not attempt the "fixes".
One can alter the course of destiny but never the destination.
Spoiler: 
