Flying the airplane is the easy part. The hard bit is responding to equipment failures and other emergencies. There is no way to predict all of the possible failure modes, nor do we have AI that can figure out how to manage unexpected problems in real time. That technology is likely at least several decades away.

There is also a sensing issue. If aircraft sensors fail then they might feed the AI faulty data. And sensor redundancy or fault detection logic can't necessarily cope with that. Whereas experienced human pilots have a pretty good record of using their organic senses to handle such failures safely.