The situations that call for a pilot rather than an AI can only be trained for in a simulator.

The (few) hours in a simulator are probably far more valuable in an emergency than the thousands of hours of real flight.

(sport pilot here) Can you explain what are you thinking about? I had a few cases of unexpected problems while flying, simulators in my case would not help at all, but it may be different for large planes with huge inertia vs my larger-than-a-kite extremely sensible 2-seater.

You can't induce emergencies in actual passenger aircraft for the purpose of training. So your only option is a good simulator.