>> Take any airliner, knock out all its control systems, and it will continue to fly.

Until they hit an AOA that puts the tail in the wind shadow of the wings. Then some will pancake. They can slip sideways into scary turns/dives and will not recover on their own. And they are delicate. It doesn't take too much force to twist them out of shape.

Aerodynamic stability doesn’t mean it’ll automatically recover from a stall. It means that if it’s flying in a steady state and you perturb it, it will tend to return to the original state.

In a deep stall you can’t recover from, it’s because the aircraft’s stability is greater than its control authority, not because it’s unstable.