They Come, They Fight, They Destroy by Tom

THE MAN IN BLACK: Still trying to prove me wrong, aren't you?
JACOB: You are wrong.
THE MAN IN BLACK: Am I? They come. They fight. They destroy. They corrupt. It always ends the same.
JACOB: It only ends once. Anything that happens before that is just progress.

With the revelation that Jacob's touch will not allow someone to die by accident or kill themselves, and the added information that The Man in Black cannot kill any Candidates either, we realize that the only way our heroes will bite the dust is because of each other. That's why this story is not really about the game Jacob and MIB are playing: they're not playing. They don't make the choices. Their "pawns" do. MIB's wager is that it will end in death, it always does: no Candidates will be left standing, and with Jacob dead, no new Candidates will be forthcoming. This really is the end-game. Jacob has to find a replacement, or something bad will happen. Jacob's wager is that ultimately, good will prevail.

Some additional supporting theories: Locke was touched and couldn't die. He survived the fall from the building, he survived the plane crash, he survived the Dharma Pit - yes, he was shot, but the shot didn't kill him instantly which is enough for the Island to help him. The only reason he died is because Ben killed him - one pawn against another, which is fair game according to the Rules. Jacob couldn't die either. Again, it was Ben who had to do the dirty work. Jack couldn't die: he survived the crash, he survived the suicide attempt on the bridge. Even Michael, who we didn't see touched, obviously, couldn't die: he only died because of Keamy's dead-man trigger, which was set off by... Ben.

This is also part of the reason why MIB needs his army: he personally cannot kill the Candidates. But his minions can... by choice.