You only live once, but if you do it right, once is enough.
— Mae West
It does appear that in the original writer's guide, there was no mention that the island's location was some fore hell, cosmic limbo or the underworld. However, it never said that it was not. It was all cloaked in the vague title of being mysterious.
There was also no mention that everyone died in the plane crash. The presumption is that the main characters we saw in the pilot episode survived the crash. We saw people who died as a result of the crash, or died shortly thereafter due to their injuries. And this suspension of belief that people could survive a high altitude midsection separation plane crash was clearly what the network executives wanted when they said they wanted a "real life" version of Survivor.
So, in some literary aspects, the main characters did get a "second" life . . . a means to change their prior lives as they tried to rebuild a new life on the island. This could have been the keystone to the entire series: new lives by building a new community.
A more convoluted character survival story emerged in the show. It was more about individual character reactions than a group dynamic to solving problems. Flashbacks took precedence over the fundamental daily survival issues mentioned in the guide.
In fact, several characters had more than one life on the island. Patchy seemed to have been killed multiple times. Sayid was reincarnated at the temple. Flocke was stabbed and did not die. Jacob, Alpert and MIB were immortal beings. Physical ghosts wandered the jungles. Whispers were trapped souls of spirits. Those elements shaded gray the actual black and white concept of either life or death in survival terms.
If survival was going to be the cornerstone theme of the series, the LOST lost its way at some point in Season 1 after the original story ideas dried up or were discarded by the writers. Instead of the survivors banding together to fight common issues like food, shelter, safety and security, it splintered into smaller groups and alliances which acted independently of a common cause. The background characters quickly turned into a malaise of unimportant plot point fodder such as red shirt deaths, picked off one by one when the danger meter ran low.
As LOST progressed, it had very little to do with "how" you lived your new island life. Bad people like Ben were not punished (by not going to the sideways world heaven). Even good people like Helen and Walt were missing in the end.
LOST could have been a once in a lifetime show. However, since its conclusion, its staying power in American culture continues to wane. When people mention LOST today, there is a negative connotation to it - - - based upon the final season. At comic culture conventions, people are not clamoring about in LOST costumes - - - like other high profile franchises like Star Wars or Star Trek which had their classic high runs more than 30 years ago. LOST itself does not appear to have its own "second" life renewal like those star franchises. It seems like the LOST universe is collapsing upon itself in its own black hole. Which is a shame because some fans rode the LOST bandwagon as the time of their lives.