There's no doubt that advanced electronics have transformed every aspect of today's cars. They are safer, faster, cleaner, more efficient , more connected and more capable than ever.
The downside: As cars get older they could be more difficult and expensive to repair, especially as high-quality electronic replacement parts become more difficult to find. Think about it. Try getting a computer or television from the 1990's repaired anywhere easily. Chances are, the technology is long out of date and there's no one readily available with the parts, experience or tools to diagnose the problem. The same thing is happening with cars.
With automotive technology changing as rapidly as it does, there's no practical way a dealership can stock anything for older cars. About 10 years is their current limit for factory replacement parts. And as emissions standards are tightening, this further shortens the production life of many components. Once they stop producing a car, the manufacturer will allow an aftermarket supplier to make replacement parts. Sometimes these 'new' parts work as designed and sometimes they don't. Let's say an older car needed a mass air flow sensor and oxygen sensor. You can buy the parts from said supplier and after replacement the mass air flow meter may not work right out of the box and replacing the oxygen sensor can introduce new problems once you start the car. This can create more codes that need to be diagnosed and many shops no longer carry and maintain the diagnostic equipment needed.
Unfortunately, mass electrification of the automobile is not allowing for a long-lasting car. We can rebuild a 1965 Ford Mustang in looks and performance but will you be able to do the same with a car made today in the year 2063?