jcjeant
Most aircraft at altitude are close to coffin corner it does not matter that it is FBW or conventional. You are not supposed to fly FBW aircraft expecting the protections to save you.
As for AF447 we will never know unless they find the "orange-box" and are able to decode it. So don't conclude that it is a FBW design fault, that is just pure speculation on your part without any evidence to support it.
BOAC
Why are you concerned about T A G "lessons" being the only ones?