Point #1 - Nothing against them, I have my PPL myself and have a few airline pilot friends.
Point #2 - Well the thing is that flying a plane is easier than driving a car. I mean by a lot. So if you can get the self driving cars working (and they are soooo close even now) then planes will be a piece of cake in a few years.
I do concede though that getting the avionics and systems certified is an order of magnitude harder than cars, because the authorities will want more evidence that it’s safe for passengers. But that will get sorted.
Point #3 - You have layers of redundancy to make it extremely unlikely all systems will fail. You could have 8 different computers scattered in different locations in the aircraft, each alone able to fly the aircraft - each with it’s own independent backup power supply systems.
The fly by wire airliners from Airbus and Boeing have never suffered a total fly by wire system failure which lead to the plane plummeting out if the sky - so even that proves we are basically there with 1980s tech. The challenge is the integration of it all.
Plus the computer processing power companies like Nvidia are developing is insane. You could literally have a plane that detects, diagnoses and remedies a problem or fault, faster than a human can blink.
Point #4 - Dunno… they are smart guys and girls, they will find something else to do I’m sure.