The ending to Lord of the Flies is extremely inaccurate. Realistically, if the boys had become that uncivilized, honestly they were about to kill Ralph, the second an adult appeared on the island they wouldn't just "magically remember their morals". I think it would be a more appropriate ending if either the navy man didn't show up, or when he did show up Jack had the boys hunt him as well, eliminating any hope of rescue. If option one occurred, it would result in Ralph's death which would signify that the two different "governments" cannot coexist. If option two was to happen it would exemplify  how Jack would do anything to stay in power even if it meant not getting rescued.

Humans are naturally only concerned with themselves and their own survival.