The making and using of stone tools leave a lot of refuse that shows up in the archaeological record. If hominids keep showing up in places only accessible by boat or Olympic class swimming then are we simply missing the evidence of the enabling technologies?
You can check out https://en.wikipedia.org/wiki/Pre-Columbian_trans-oceanic_co... for some debunking.
Most places on earth, America included, are or were reachable in small watercraft at certain times of the year, even without sail, given certain weather conditions. Only the remotest islands truly required advanced seafaring for repeat navigation.
Anyway, aside from isolated boating incidents there are far more impressive stories that are buried by popular history and its political supporters - the use of Persian as a lingua franca for trade and diplomacy as far away as China, various Indian Kingdoms throughout Southeast Asia and up to the Chinese border, entire civilizations whose expanse was extremely significant but virtually nobody has heard of, successful cultural genocides on grand scales, etc.
Unless the reason these early populations have been replaced by Polynesians is because they weren’t diverse enough and faded out...