Especially AF296 killed 3 people when they try to demonstrate the anti-stall capacity of the FBW during an airshow. Airbus modified the way the fbw control reclamation worked after this. After the Rio-Paris accident (forgot the flight name, it was AF too), they changed the way the degradation worked wehn sensor fails (i think now 3 different mode exists, and information is more visible).
Those incident killed people, and there is a chance that the first one was actually caused only by the manufacturer (the second one was 99% the pilot though, the remaining 1% was: better information, better sims and better gradation so that even new, tired pilot can't make this kind of mistake).
FBW adds cyber-related failure modes, but it is hard if not impossible to make the traditional hydraulics, strings, springs and pully-based systems resilient against failures since the number of things you have to duplicate explodes exponentially.