Aviation involves constant unpredictable human inputs and physical states. Hundreds of vehicles, not installations designed to have as few moving parts as possible. It is not yet solved, the status quo merely has a societally tolerable death rate. There can be new sensor hardware, more safety redundancies, and info synthesis/notification interfaces that are currently blocked by old hardware bottlenecks. Controller and pilot time and attention is limited, and it can be wasted less.
And inversely... when pilots leave too much to automation, their skills may degrade to the point that by the time you actually need a capable human crew because something has gone terribly wrong, the capability of that crew has degraded too much, and the FAA has warned about this in the past [1].
[1] https://medium.com/faa/the-dangers-of-overreliance-on-automa...