A retired airline Captain was on a radio show last night. This guy has over 35,000 hours. He said that while it is hard to understand, when you are flying oceanic you are "on your own". A controller called in and said ATC is more concerned with maintaining separation so airplanes don't fly into each other. One of them said something about satellites but that the technology just hasn't made it's way to civilian air - cost, dealing with a hundred different versions of the FAA, etc.
Emergency beacons don't work too well under that much water. The captain said they'd need ships with underwater reception ability.