There is little value in considering replacing humans with computers in the short term; similarly comparing current operations with future developments.
Future operations will be innovative, evolve as a combined Man - Machine team, each contributing to their particular strengths.
New design concepts will enable single pilot operations with economic benefit. Some highly automated systems are already capable, but without technical enhancement may not have sufficient redundancy for an acceptable level of safety with single crew.
A critical 'failure' is pilot incapacitation; a rare event nowadays - not that rare for a single pilot when considering the overall level of safety.
Semiautonomous operation (automatic recovery) would only be required after the first failure (no human), and depending on certification requirement - probability and capability - avoiding adverse consequence. A 'relatively simple' recovery system might be sufficient; it would not have to manage pilot + lighting strike, etc - excluded by certification probability, just a lower minimum standard with accepted risk.
One problem is the level of piloting skill for one crew operation. Current operations have opportunity to improve experience; First Officers aspire to Captaincy, but perhaps with less experience than in previous operations. However, with single pilot ops there may not be any opportunity to learn on the job - no FO, thus the automation will have to compensate for reduced levels of experience within the pilot-automation team. However, the need for further improved technology may be no more than would be required for abnormal flight without a pilot, although the tasks differ.
Airbus is thinking ahead, considering means, method, and validation; most of all they are not depending on simulation. Their tests are real, man and machine, warts and all, to provide a wider experience base and safety confidence in choosing a way forward.
Background reading; 'Complex Operational Decision Making in Networked Systems of Humans and Machines: - Integrating Humans, Machines, and Networks: A Global Review of Data-to-Decision Technologies'
https://download.nap.edu/cart/downlo...ecord_id=18844 'Download free pdf'
Summary ~ page 16, with interesting findings.
Chapter 3 is a valuable view of the human element - HF, CRM, etc.