Olmec culture in its most distinctive form had already gone into decline three to four hundred years prior to this point when the Jaredite polities (there were at least two) end. Nevertheless, post-Olmec peoples (including lineal Jaredites) continued.
Ether also prophesies Coriantumr’s travel to Zarahemla and his sojourn there: “He should only live to see the fulfilling of the prophecies which had been spoken concerning another people receiving the land for their inheritance; and Coriantumr should receive a burial by them.” Inheritance by this people who would bury Coriantumr is an interesting prophecy. The Zarahemlaites were Mulekites, had reached the New World more recently than the Jaredites, and therefore could be seen as a new people who would inherit the land. However, they had also been part of the Olmec world. In other words, although the Mulekites had been among the Olmec polities, they had not been part of the specific Jaredite polities active in this final war. If they had been a splinter group from these Jaredite polities, Ether/ Coriantumr would probably have considered them part of his people, not “new” people who would inherit the land.