What does the AF 449 crash have to do with the existence of a button to return the aircraft to wings level + zero vertical speed?

To answer your question though, LVL has been around for close to two decades now. IIRC there was a Cirrus/Garmin partnership that added it to the latter's G1000/GFC 700 and it's since trickled out to other consumer-grade autopilots.

they were disoriented because a sensor was frozen or something like that and the readings were not correct if I remember correctly, an automatic system would have received the same wrong information.

IIRC, they were dealing with frozen pitot tubes or other sensors that were keeping the air data computing hardware from getting valid input. An automated "Get me out of trouble" button might have had the opposite effect.