The cynical part of me thinks everyone involved knew what had happened on Sunday. There was ample evidence that the submersible imploded (repeated stress on a carbon fiber frame, zero regard for safety, the fact that all communication was lost permanently). Then there was the fact that the logistics involved in a rescue were basically insurmountable. The Navy/Coast Guard saw this as a good live training exercise and the media got a great story. No one was gonna ruin things by admitting that the whole thing was hopeless and not really worth pursuing.