Lengthy Flights Over Water
Just as a matter of interest, has anyone ever compared the long over-water routes (eg Aus to South America) to the shipping lanes and how busy they are?
If in the unlikely scenario of a flight coming down in the wide expanse of the Pacific, one's chances of survival would be moderately enhanced if there was a steady stream of freighters sailing past to effect a speedy pickup.
However I'm guessing that if the aircraft's route requires a lengthy ETOPS rating then that naturally means that there's never a whole lot of anything (let alone a usable airstrip) down on the surface under some parts of the route.