If one looks back at the legacy of LOST, it was a dark friend who could not find his final path.
It began as an action-drama in the vestiges of tales of shipwreck sailors on uninhabited, savage tropical islands. The viewers were drawn into the story as "what would I do?" "How would I survive?" and "This is what I would do" questions in their minds. But we quickly saw the reality of the situation: death. Tragic death.
It quickly shifted to dramatic politics as alpha males started to lobby the survivors to impose their dominance over the group. Jack was the reluctant leader, over the burning desire of Locke and the self-interest of Sawyer.
But the leadership issue was secondary to the instinctive greed of the castaways. Survival of the fittest was the rule of the day. Sawyer began to hoard valuable things which made him into an outcast, a role that he enjoyed. Because he had no connection to the group, he could con them out of their perceived valuables. Kate also fell back into her pre-island survival tactics: charm and escape.
As the days, weeks and months went on, darkness beset our friend. We would see the return of the inner madness in Hurley as his imaginary friend tried to convince him to kill himself. Sawyer would not hesitate to kill Locke's father in a "deal." The Others, especially Ben, had no remorse in ruling by fear and death.
Even the island's guardian angel, Jacob, did not intervene when his Temple followers were massacred by his brother. We were told that this cycle of human carnage was the norm for the Man in Black in his game with Jacob.
In a sense, whether you thought it was true or literary, our island friend was in purgatory; a place where one could not leave on your own - - - trapped in the deepest, darkest and troubled portions of your personality.
It has been said that it always darkest before the dawn. Before the final duel with MIB, the island was in chaos. Splinter groups hid in terror or joined the hunt to destroy the remaining castaways. It was only when Jacob "died" to give Jack the magic power to defeat his brother, did only a handful of people could break their physical and mental chains to leave the island cesspool of damnation.
We never saw what the dawn of a new day would have brought to the survivors who flew off Hydra Island in a broken airplane flown by an alcoholic pilot because the show diverted into a parallel universe. The flip side of darkness, a lighter more gentle (almost medicated) view of the main characters. But even then, they were subconsciously haunted by their island past.
In the end, when the full light engulfed the church, no one can say for sure that anyone found true redemption, true happiness, or even hope of enlightenment. The white light like white noise was a background element that erased the moment only to leave lingering questions in its wake.