“Hypoxia triggering an event on a commercial airliner is extremely rare, and when it occurs does not result in an impact in 10 minutes. There is nothing “insidious” about a loss of pressure on an Airbus. I am an Airbus captain.”
Then you also know that it can, and HAS happened.
Helios 552, a 737-300, in 2005, for instance.
Helios flew for a very long time after the event. Turkish F16s were scrambled.
This happened in less than 10 minutes. There is no automation that would descend an A320 at more than 2,000 feet per minute from altitude unless intentionally directed by the crew, and if directed they were conscious. Even turning off the autopilot would not result in a steep descent like this.
A crew-initiated emergency descent would have descended at a lesser rate of descent, and that type of descent starts with the crew setting the floor,= altitude, which in the case of no terrain is never less than 10,000 MSL - and ALWAYS on autopilot. If the crew was cognizant of terrain, they would have set an even higher altitude. The terrain there is less than 10,000 MSL.