This theory is substantially less likely for a few reasons:

* The predominant oceanic currents in the South Pacific around Rapa Nui come from Polynesia, not South America. So you're not likely to be drifting towards Rapa Nui. Indeed, traveling from Polynesia to South America via Rapa Nui isn't a particularly far-fetched idea.

* Polynesia, and earlier Austronesian antecedents, had a much stronger tradition of long transoceanic voyages. (Austronesians crossed the Indian Ocean and settled Madagascar before Africans set sail from their own coast to reach it).