What if the loop is not about timelines or anything what if it's just a metaphor to something else and that something is THE MANKIND - when MIB told Jacob "They come they fight they corrupt they destroy,it always ends the same" it's MIB's point of view that the mankind are the ones who always start wars n fight each other , kill each other always the outcome is death and loss. it's just a loop that never ends from his point of view.But Mr Jacob doesn't think so he sees that it only ends once , anything before this is just progress meaning that all these wars and destruction are just steps to the end which is maybe further creation and peace.That's why when MIB told Jacob that one day when he finds a loophole he'll kill him and that loophole is indeed a man(Locke)who had specific qualities the MIB had seen in him from the beginning that served his plan in fullfiling his goal.Through time MIB and Jacob were playin! g games to see who will be right at the end , this can be seen clearly when MIB asked Jacob who brought the ship and jacob answered that it was him. All through time from the beginning MIB was searching for this loophole to kill him until some day he succeded in finding that loophole but did MIB win the game at the end ???? that's the question to be answered in season 6 and I suppose when JACOB touched Jack,Sawyer...etc that is their destiny to become in this final game , that's why they came to the island in the first place which is the real reason behind all of this and NOW DESTINY IS FOUND
