I think people underestimate the amount of infrastructure that would be required to make pilotless airliners absolutely safe.
The fancy new cars with the driver assist sensors have issues in rain. And construction. Not to mention both. Jeppesen charts take weeks, sometimes months, to update taxiway changes. Fly to somewhere in Central America and think about a computer that could handle BOS LAX on a good day, handling a Central America turn with pop up thunderstorms all over.
It is certainly possible to go fully automated but when you look at the infrastructure standards which must be met at airports, and the burden of aircraft and navigation systems redundancy, pilots might not seem so expensive to keep around.
I had to abruptly modify a flight path to avoid flying directly through a large flock of migratory birds a few trips ago. Not sure a computer could have sensed the threat. (Then again had it been nighttime I wouldn’t have sensed that threat either.)