True but these days it's very very hard to know everything actively. There's just so very much.

It's understandable when a pilot forgets about that one obscure button that's only used in some edge case only happening on one in 100.000 flights.

These days being a pilot is a lot like being a system engineer especially since the dedicated flight engineer position is gone. Yet also requiring the spatial awareness and manual skills of flying. I'm often surprised how well it still goes with the complexity of modern aircraft.