The whole point is that they are not _constantly_ monitoring, because again it’s not something people are physiologically capable of.
The difference in aircraft autopilots is that if you take 5 or 10 or even 30 seconds to notice an issue, you correct. Whereas for “self driving” you have 2 seconds or less, and are expected to have complete situational awareness for the entire time. [edit: to notice non critical problems, immediate response failures have significant repetitive training to cause immediate correct response - stall, tcas, mcas, etc]
As in, the defined “correct” way to use self driving cars is to have as much focus awareness and concentration as you use while actually driving, only without actually doing anything at all. Which again, is not something that any person is capable of doing. This is established, even in the context of pilots.
In the context of commercial pilots as I understand it, autopilot is often disengaged for the purpose of ensuring they’re engaged (in addition to standard elements of not getting rusty).
And again, if the autopilot fails in flight, pilots who are trained specifically to deal with the myriad issues and complexities of failures and autopilot disconnects, have literal orders of magnitude more time to react than untrained occupants of “self driving” cars.
Referring to autopilot not existing in terminal or during takeoff/landing (though I do understand ILS or similar can handle normal landing?). Those are times when the pilots are actively engaged in operating the aircraft (even with ILS).
The issue with autopilot/self driving is not what happens while operating in an environment that requires active engagement by the operator (pilot or driver), nor what happens at points of engagement (start or end of travel, making adjustments to travel), it is that humans are physiologically incapable of maintaining engagement in an activity if they are not actually involved in the activity. Again, this is something that has been established in study after study, and applies to extremely well trained pilots responsible for hundreds of lives just as much as it does random driver.
These cars “self driving” systems require the occupant (they are not driving) of a car to have greater control and engagement, and faster reaction times, than a trained pilot, in a system that has even less cause for engagement.
You referenced how autopilot in an aircraft requires adjustments (which as far as I understand are not being made constantly, but no matter, let’s assume they are), “self driving” cars do not even have that. The argument “aircraft autopilot requires engagement from the pilot” does not make my point about “self driving” cars incorrect: it in fact further demonstrates how unsafe “self driving” cars are - pilots in this model do have actual engagement with the operation of the self flying plane, in addition to increased training, significantly larger time to react, and significantly better response options when no-delay responses are needed.
Self driving cars say the occupant is required to have greater engagement in driving the self driving car, while doing less, having less training, having less time to gain full situational awareness, having less time to respond when the system fails, and not having any clear response options or training for immediate-response-needed events.
I’m genuinely curious, and I’m sure that NTSB or FAA must have published some statistics on the amount of time pilots need to notice and respond correctly to different failure modes.