Remember the end of Lost? Could it be that Kevin returning home to his whole family means that he is really dead and this is the afterlife? Oh wait, I just read the set-up for next season. Afterlife in Australia?
shareNo, all the people who disappeared will come back. Plot twist: they come back dead. They will bury them and gain the closure they need... end of story. Nobody will ever know what really happened.
shareLOST was a terrible show after roughly the third season with not a single intelligent/realistic character, but it did explain everything fairly clearly.
This show is a different animal--it's clear since the beginning that there isn't supposed to be an explanation. The show is about how modern humans react to a "mystical event" that has no explanation and never will have an explanation as to who/what/how/why etc it occurred.
Lindelof said right at the start of season one that he was going to answer the mystery this time. I doubt he will, but he said it.
During their talks, Lindelof and Perrotta agreed the answer to the question "did matter and [viewers] needed to know."