My understanding is that airline pilots only use autopilot when at cruising altitude. At those heights they have several minutes to take over and fix a problem before crashing.
Automatic landing systems are mandatory for category III ILS approaches. You can search for ILS IIIb on YouTube to find examples of landings where pilots can basically see nothing until they are seconds from the ground.
If a malfunction happens during landing, you definitely don't have several minutes to rectify it.