> Modern cars that have electrical issues cannot be fixed.
Some of it is just "volume" too. When you scale up the amount of wires and connections so much that formerly easy problems become impossible. Things like a somewhat buried wire getting some exhaust heat because a plastic retainer failed, or a squirrel getting into the engine compartment and chewing. You can sort that out in a car with dozens of circuits, but it's harder when there's hundreds.
Some of it is just "volume" too. When you scale up the amount of wires and connections so much that formerly easy problems become impossible. Things like a somewhat buried wire getting some exhaust heat because a plastic retainer failed, or a squirrel getting into the engine compartment and chewing. You can sort that out in a car with dozens of circuits, but it's harder when there's hundreds.