"Self repairabiliy stopped being a thing in the, IMHO, mid 80s."

This really isn't true. Cars all the way up to the mid 2000's are very easy to work on and repair. I have always done all of my own repairs. Domestic cars even today are still easy to work on. Yes you need a diagnostic tool to do some more advanced diagnosing. A $300 Autel will do most things, an $800 Autel will do nearly everything. Yes it is an expense but it can pay for itself in one repair when you factor in labor costs at a mechanic. And that Autel will continue to work for all of your repairs the next 5+ years.

You need to buy $300+ worth of mechanical tools to work on your 1982 Range Rover.

You need to buy $300+ electronic tool to work on a modern car.

I would say German cars from the ~2010's up are out of reach for the average person to repair, they are using fiber optic networks and complicated engine management systems. But everything else is really isn't that difficult if you have a basic (High School Level) understanding of how electricity and computer networks work.

Around 300 bucks is about right. Good thing is, it's all basic mechanical tools that do a lot of other stuff. And it includes the specialized tool, e.g. for the carbs and the prop shafts. The same tools are needed for the mechanical repairs on modern cars as well, so.

Some power tools help, again those do other things as well.

If you cannot do most of the repairs on an old car yourself, they are unaffordable. Garages, if you one willing to work on them, charge around 100 bucks per hour where I live.

My problem is, despite being an industrial engineer, I seem to have a blind spot for electrics and electronics. Mechanics are much easier. The main reason I will never switch to eletronic fuel injection, I can rebuild the carbs in the desert and can calibrate them. EFi goes over my horizon so.

Fortunately the $300+ worth of mechanical tools also fix other things like appliances, etc.

> Self repairabiliy stopped being a thing in the, IMHO, mid 80s. For a lot of stuff.

Was it emission control stuff? Computer controlled fuel injection?

Definitely was a different era when you could rotate the distributor to advance/retard the timing.

Keep in mind that third-party diagnostic equipment is almost always based on reverse-engineering and may lack some features, and original equipment from the manufacturer is rarely available.

Only partially. I used to work for a third party diagnosis tool company, and we had direct access to information from all companies, which they had to legally give us. I still reverse engineered a lot of things because when I.didn't understand the spec seeing what their tool did made it make sense.

I haf this discussion with mechnic friend a while ago, obviously not not a 40 year old car so. Our true second car is now, I have to guess, 15 years old. Diagnostics are no problem, computers with the correct software are around 400 bucks. Cheap enough for either an enyhisiast or free mechanic. The main car is 4 now, diagnostics equipment is only OEM, and goes for 5 figures. Go figure, but it explains why diagnostic jours can be so expensive.