The Easter Islanders came to their island due to over population of the other 'Oceana' islands.
Easter Island was the last in a chain of islands in the Pacific. Is was not uncommon for these people to find it difficult to continue paradise on their home islands as their numbers grew and subsequently set out to find yet another island paradise to contiue their lives.
This was the fate of the Easter Islanders. They landed in boats carved out of trees and set up housekeeping no different than their ancestors before them.
The problem arose with the Easter Islanders when their natural resources could not keep up with the next generations of people. They literally deforested the island as their population grew and depleted their fisheries. They destroyed what was left of any wildife of the island without realizing it was necessary for their survival. What they managed to maintain to some extent were domesticated chickens they had brought with them. But, it was difficult raising the chikens under stone mounds to protect them from the sun.
Water became an issue because the forests were gone and the tropical rainfall that supplied their 'rain barrels' full of fresh clean, salt free water no longer existed.
With their hardship realized, their holy men decided the gods could not find them in such a distant place and set out to build larger and grander stone statues as they lined the shores.
The island itself, over time, became divided into separate tribes or villages if you will. There were three that can be discerned, although I am confident some small collection of peoples were lost in decaying evidence. They didn't war among each other as one might expect. The island was too small to support war. So, they chose to become 'status' symbols of authority and the stone quarry became a place of wars to build the largest and best godlike depiction and to move it to the shoreline where 'the eyes' of the statues would find the missing gods.
There was one island off the main island where a group of brave men decided it was the place they would find a new religion and they called themselves "The Bird Men." They would dive off of high cliffs into water with questionable outcomes. But, the one to survive the dive and swin to the not so distant island and return with a bird egg was hence the leader and would save them all. That culture was short lived.
That is what occurs when religion and social order fails a people, they seek to understand a new reality through 'other spiritual' means.
Needless to say the only objects that would survive a deforested island would be stone statues and a quarry where they began.
