In a 2017 article, Jeff Jensen wrote that LOST producers were banking on a massive volcano story line to wrap up the island origin of the smoke monsters, but ABC refused to pay for it.
The use of the volcano was supposed to show us how the smoke monster was created, by Jacob throwing his brother into it. In many cultural myths, sacrifices to the gods used volcanoes as part of the worship rituals. The producers wanted to use a temple with the volcano scenes, but ABC balked because creating temples were expensive.
The show did show a temple with very detailed ancient Egyptian signs and symbols. It was the place where the Man in Black took his angry revenge on the remaining Others. This temple appeared to be the root of Jacob's power over the people he brought to the island. Its priest held forth a cult in which the spirit or smoke monster could not enter until it reached human form.
A BBC article stated:
Often cultures have seen active volcanoes as the abode of gods - typically gods quick to anger.
think the creation of myths is essentially the human reaction to
witnessing a natural process that you cannot explain, says Haraldur
Sigurdsson, a U.S. volcanologist “So you attribute it to supernatural forces and you say it is a battle between the giants and the gods.”
Was the island story a battle of angry gods, Jacob and his brother?
If true, then how could simple human beings defeat them?
The Man in Black, smoke monster, believed he was trapped or imprisoned on the island. Jacob claimed that he was the guardian of the island. Was Jacob the prison guard to MIB? Was his sole purpose not to unleash an evil spirit upon the world? The island was phasing in and out of the Earth realm to be hidden from humans, because they would be drawn into using the evil to destroy the planet?
Was Jacob bringing humans to the island a means of appeasing MIB? Instead of playing ancient board games, the two devised a game using humans as pawns.
But at a certain point, the brothers grew tiresome of their company and their mutual curse of being trapped on the island. For Jacob to be released, he would have to trick a human to become the new guardian. For MIB to be released, he would have to die which is difficult for an immortal spirit.
It is interesting that the show runners and the network were at odds on production budgets to the point where the story had to change. This confirms some skeptics who said the writers were making up the show on the fly. The fly was the network not allowing them to produce their vision.
But would have the volcano story line "solved" the ending issues?
No. Even if the whole general premise was overlaid with Polynesian mythology of volcanoes, gods and sacrifices, it does not explain the sideways world, the parallel universe, the Flight 815 plane crash and the ending in the church.