I don't fully agree with all of your premises, overall, I think the main focus of your comment is true. This ain't your dad's Oldsmobile.
In the past I could use some logic to troubleshoot a vehicle. When I say logic, maybe it wasn't really true logic, but rather experience from 40+ years of working on traditional vehicles backed by the experience of my dad, a boss who ran the machine shop where I worked my way through college, and various other real world experiences.
The past 40 years mean little to the recent products. Things are much different today and you really have to keep up not just yearly but monthly. Not easy to do if you are not going to regular training or receiving regular information and updates.
Machine Shop? That is great but what does that do for new technology they are putting out regularly? Logic no longer applies just training and education.
I work in the Performance industry and try to keep up with training and even then it is difficult. I also have many friends that are techs that own their own shops and or work for GM dealers as techs and or service managers.
Even on my last vehicle I had to work with a GM performance driveline engineer to resolve a nagging issue on my 300 HP DI Turbo 2.0 Chevy engine.
I too have worked my way through life and put my self though collage but none of my past helps with new technology today.
the computers in these vehicles are much more advanced today and can do some really amazing things. They mostly are all the same just the programming differs per application. But like so many other things from spacecraft, planes and even boats these computers are programed to kill non essential systems when power is down. They are programed to work in a neutral mode when a sensor fails to give you a safe mode to get home or to a dealer for repair.
The demands for power in todays cars need to be managed as you are still using the same 12 volts that we have used since the 50's but now with so much more demand. Electric power steering. High Voltage injectors. The entertainment system alone.
This is why automakers will up the voltage very soon.
Just the injectors on this truck crack a heavy punch as we are now seeing fuel pressures of 2000-3000 pounds at the injectors and it takes a lot of voltage to fire that injector open and closed.
So you can disagree but the real question is what have you done lately. I am not trying to be smart but so many people fail to realize how much has changed and if you do not keep up you will be left behind. In todays products you can never assume anymore based on past experience or you will end up with an even bigger issue on your hands.
I know a lot on cars. But even today when I get into new things I really do my home work before I get into it. Even simple things we used to do in the past no longer apply.
The key is to do as I am doing anymore I know some but there is much more I need to learn.
The truth is we are way past what your fathers Olds was. We are far past what NASA used to get to the moon is a little closer.