So many questions:
Why did MH370 turn off course?
Was there a decompression?
What stopped all electronic transmissions, including automated ones?
How did it keep flying with so many systems not working?
Who commanded the descent to 29,500?
Why no transmission from 200+ mobile phones?
If decompression, why not a further descent?
If on AP with everyone on board unconscious and 2,000+ miles range, will we ever find it?
Obviously there was some sort of event but really we have no clues until we have answered some of these questions.
If the primary radar comes up with an accurate heading then it might be possible to follow the track. But it would still be a needle in a haystack.
Maybe a submarine with a towed array listening for the FDR & CVR pingers could be tried.