At the end of this movie, what if...

Let's say Richard, Lilli and their family get sick of the island, and want to explore outward. Say Richard or another family member made a boat, followed the tribe that did sacrifices and burials on the island, and then worked their way to other, charted islands from there. They would eventually find another ship that would get them back to civilization, and maybe the next representatives of civilization wouldn't be so unappealing to them. Let's face it, between the snotty daughter Sylvia and the thieving rapist Quinlan, they didn't get a really good taste of civilization. (in fairness to the rest of the crew, they weren't too bad. Even Sylvia wasn't really horrible, and Quinlan got eaten by a shark.)

I think they change their mind over time, curiosity and boredom would probably get the best of them.