Plain And Simple
Ok i havnt posted anything on this season yet because honestly their hasnt really been a lot to go on but after watching the Richard centric episode it kinda brought a lot of things together for me regarding the main storyline in lost, in my opinion most of seasons 2,3,4 and 5 have kinda been filler and the writers could of wrote this in probly 2 seasons which im sure i have heard somewhere that was the idea when they started writing it. To sum it up the island is a prison and jacob is the prison warden, their it is plain and simple job done.
When jacob showed the bottle of wine to richard the evil he spoke of was mib, the bottle was the prison and the island (the cork) was what was stopping him from leaving, when he smashed the bottle that was mib saying im not playing by the rules no more and im getting off this island whatever it takes.
Lets say mib and jacob are 2 god like beings ( i hate refering to them like gods but i have no other way of describing them ) They ruled and watched over the world together they were worshipped and loved but mib grew tired of humanity all he saw was the bad in people they were all sinners and everything that was given to them they corrupted so he decided to rid the world of humanity. jacob did not like this he loved humanity and thought they were worth saving so he had to stop mib. He created the island to act as a prison and seperated mibs essence from his body and trapped it on the island and made it his purpose to guard over the island for eternity and stop mib from ever escaping and destroying humanity. While he is watching over the island and mib, jacob keeps bringing people to the island to try and prove to mib that their is good in people and that they are worth saving in the hope that maybe mib will change.
I beleve the story of lost has always been about mib and his wanting to leave the island the smoke monster was in the pilot episode which showed us that maybe the writers actully did no what they were doing right from the start.
sorry i no this theory is all jumbled and hard to read but im having trouble getting everything down on paper i have a lot more i want to say but i cant get it out to make any sence, maybe if you guys can help fill in some gaps that might help