Granted he wasn’t flying (and didn’t try to fly, per-se), but I doubt that a single pilot could subdue someone who is tripping balls and keep a commercial airliner in the air simultaneously.
Or the many, many, https://www.youtube.com/playlist?list=PLi0SM524ylKVAo5NJNrfzPwf4mTdzLz2l other cases that don’t make headlines in which a warm spare became imminently critical for the safety of hundreds of people (both in the air and on the ground). The reason they don’t get media attention is because “Situation on Plane Ended in the Good Way, System Worked as Intended” isn’t a headline that get clicks.
Hell, even aircraft themselves are built with redundancy for critical components. How in the fucking world could one even begin to justify not doing so for us squishy humans?
It’s not that this idea is just stupid, this idea is dangerously stupid.