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.

The AF 449 was in a stall, and the pilots panicked and did exactly the wrong thing. The pilot came out of the lavatory and immediately realized what was wrong, and pushed the stick forward. But it was too late.

If the captain could figure it out, so could the computer.

I recall another crash, not so long ago, of a commuter plane where the wings iced up a bit and the airplane stalled. The crew kept trying to pull the nose up, all the way to the ground. They could have recovered if they pushed the stick forward - failing basic stall recovery training.

There are many others - I've watched every episode of Aviation Disasters. Crew getting spatially disoriented is a common cause of crashes.