I think you will always need humans in the loop.
Yes there have been far too many accidents caused by stupid or poor or bad or fatigued piloting. But I think the answer is not to remove the pilots - the way forward is to try to remove the poor piloting.
We should certainly refine the present automation so the human can interface with it even more reliably - knowing as we now do, the fallibilities of the human senses and brain. Under stressful situations our hearing becomes ignored. Tests show that in high workload situations we do not notice a person in a Gorilla suit in full view, walking amongst other people. We suffer information tunnel vision or overload, and cannot see the wood for the trees.
Pilot training should be a true measure of a pilot's skill and ability, not a box ticking exercise. How about that every year, only the top performing pilots in the SIM became the Captains for the next year? The others stay as, or are demoted to F/Os. Same thing every year, so those in the LHS would always be those with the top 50% of skill, ability and good organisation. That would remove LHS complacency or low ability. I was deeply shocked in my last SIM that an "experienced" long-haul Captain did not know how to program a hold.
Autonomous aircraft could certainly cruise unaided up where there is nothing close to hit - and as long as there were no system failures or passengers becoming ill. And when aircraft systems have been set and checked (by the pilots), they can auto-land, as we know. But what about taxiing and the nose-wheel slipping in a turn due to ice or oil on the taxiway? We humans would instantly reduce the steering angle and perhaps gently brake. I know cars have ABS and traction control using yaw angle processing, but it is hard to imagine an autonomous system being able to 100% deal with taxiing. For example a baggage truck pulling out in front of them. Or low visibility at night
And why autonomous aircraft anyway? You still need a cabin crew, fuellers, engineers, ramp agents, loaders, caterers etc etc, someone has to coordinate all those people and plan the fuel load and check weather etc. Getting rid of two people amongst the dozens needed to get an aircraft into the sky seems to me to be the wrong focus.
Any company constantly tries to reduce costs. If a weaving mill can buy an automated weaving machine that does the work of two skilled weavers and only needs one unskilled worker to oil it, of course the company will become more efficient and make more money. But a weaving machine is not an aircraft or a coach operating in four dimensions and full of passengers.