Every time there is a major World recession, Argentina has to try and pull off the same land grab. They would stand of better chance of taking over Chili since navel skills would not be necessary.
No, it is about UNCLOS, Law of the Sea, and who controls what part of the shelf and how far the shelf extends. Who gets the royalties. In this particular case there are claims and counter claims between UK, Argentina and Chile.
Given similar situations in the Arctic and the South China Sea, the US will be in there trying to limit the claims made by all three nations, preferring these areas be international waters under control of the UN.