In that last conversation, Christian, besides saying everything that happened was real (which, I know, could still be said if it was just Jack’s imagination), also says that the reason they are there is to reunite with the most important people in their lives. If we see the final shot as an indication that the whole series was a dying delusion of Jack, there is no depth to the fact that he apparently thought he was reunited with the other ‘survivors’ and that they were the most important people in his life. If the series was in Jack’s mind, he died thinking the people he most loved were people he never met and who probably never existed.
Also, what can we say about the other characters flashbacks and all of the strange things that happened with them without Jack knowing about? Did he create such an ellaborate and unnecessary fantasy just so he could be at peace in the end? Why not just create the alternate reality with the ones he truly loved (and truly had met in real life)? Why make 6 seasons of a show that amounts to nothing?

My point is, if we assume all that happened (except the sideways timeline) was ‘real’, then we had a show full of people lost in their lifes, united in an island in order to redeem theirselves and protect something mystical (that in my opinion could be the afterlife existance itself, but which is definitely open for interpretation), and who, after dying (some during and some long after the end shot) find the most important people in their lifes in order to ‘move on’ together, making lost a series about redemption and the importance of other people in our lives. If the whole series passed within the moments Jack was dying, it was a tale of the bizarre allucinations suffered by a dying man.

It’s impossible to prove or disprove your theory, and if you think this makes the series better than the alternative, it’s ok, but I just don’t see why explain it that way (I’d be happy to read an explanation, though ).

PS: I’m not a big fan of the purgatory/limbo revelation (and I’m not sure some of the sideways scenes make much sense), but I thought it was coherent with the series theme as a whole, and I really liked the ‘real’/island part of the finale.

That the last image of the wrecked plane was added by ABC does change things a bit, but even without that image, I think that the use of a different kind of transition to take us back to the eye remains meaningful enough that I would stick with my analysis. Of course, I am also very stubborn so there’s also that.

“Newsflash to anyone still thinking that all the Losties died when Oceanic 815 hit the island:

Those final images of Sunday night’s series finale—of the plane wreckage on the island with no survivors—were not the producers’ doing.

The show’s ABC rep just told me:

“The images shown during the end credits of the Lost finale, which included shots of Oceanic 815 on a deserted beach, were not part of the episode but were a visual aid to allow the viewer to decompress before heading into the news.” The statement was first acquired by the Los Angeles Times.

The images were added by the network, not Damon Lindelof and Carlton Cuse, to soften the transition to the 11:00 news.”

Extra note: My thoughts about the abrasions were just that it’s been so long that there are some things that can’t be fixed, like all the characters’ having aged so much, and that was something they just decided to let go.