The Easter Islanders were extensively studied in the 1950s and 1960s by Thor Heyerdahl, and they do (or at least did) know all about their own history, including how to carve the statues using the local materials, how they were moved, and what happened that made the process stop. The fact is, Schoch used to fit in better with the late TH than he did with Robert Bauval, and it's too bad that's no longer the case. Now he cherrypicks stuff to support whatever he's pushing in his latest book, IMHO. Heyerdahl first made the connection between the S American mainland (Tiahuanaco, as a matter of fact) and Rapa Nui, based on art and architecture. The earliest statues on the island are few but stylistically different, and resemble S American work (also he excavated thoe earlier work to reveal formerly unseen details).
Kon Tiki was the first adult level book I read that captured my soul. Just a kid it alerted my senses to learning. My addiction to hf radio and geography. It just would not let me go. I guess eventually the siren song of girls and then aviation came along and modified my interest over the subsequent decades.
But for more than a few years I wanted to be adrift on that raft leading the team to new discovery.