the whole "they're dead and in purgatory and/or hell" thing is something that fans speculated about from the beginning... my guess is that they're bringing it up in the show as a red herring or simply to disprove it and let fans no that there's no well in hell they're dead and that the show will have a real ending 
I remember reading an article awhile ago that said the producers of Lost were going to announce this summer how many seasons they're planning on running the show for, to give viewers a light at the end of the tunnel for when the final answers will be revealed
I remember reading an article awhile ago that said the producers of Lost were going to announce this summer how many seasons they're planning on running the show for, to give viewers a light at the end of the tunnel for when the final answers will be revealed