Biggest issue with autopilots is that, well, they're part of the machine, the human comes in very important when the machine is partially crippled - we've already seen what happens to automation when critical sensors fail in the 737 Max.

> You can’t blame a machine but you can blame a person when an accident does happen. Accidents can be happily resolved as “pilot error” without having to call back the entire fleet of aircraft.

That's not really the case, air accident investigations won't blame the pilots just because they're there. They'll happily point out design defects, or maintenance failures, or pilot error, if it was actually a contributing cause.

Of course, plane manufacturers love being able to blame the pilots when their autopilot engages Kill All Humans mode.