Another flight may have heard a mayday. A mayday might have given the rescuers a clue where to look. A mayday might have launched the search effort within minutes instead of hours later.
It wouldn't have saved the aircraft but it might have saved a lot of effort finding the accident site and, consequently, the flight recorders.
Since I'm apparently as thick as a plank and you apparently have more knowledge about what was happening in the cockpit than the entire French investigation team, I'd suggest you call them and offer the inquiry your expert opinion. It's clearly wasted here.
Yep, that's right.
When I'm trying to save the lives of hundreds of passengers and crew (not least my own!!), a MAJOR priority is making sure they know where to look for the bodies should I fail........
MONUMENTALLY stupid initial comment, made all the worse by the above attempt to justify the indefensible.....